With the nomination of Ronald Reagan assured, political leaders and analysts in major world capitals have been prompted in the last few days to take a new look -- in many cases their first serious one -- at the man whose candidacy until recently was largely ignored or scorned abroad.

The sudden awareness that the conservative one-time screen star could become the leader of a superpower within months has led even the media of the Soviet Union and China to drop their name-calling and produce amiable profiles of the Republican candidate for their readers.

Until recently, governments of all stripes -- from the Soviets to the Israelis to the Indians -- dismissed Reagan as a peripheral figure representing one of the more puzzling aspects of American presidential politics.

Through the spring's primary elections, Regan's candidacy, while doing well among Republicans in the United States, found little sympathy abroad except among South Africa's whites, Taiwan's nationalist Chinese and Latin American military regimes.

According to a survey made by foreign correspondents of The Washington Post, however, politicians and press of the center as well as the right in countries such as Britain, France, Egypt and India now are feeling compelled to seek out, and find attractive facets to Ronald Reagan.

Even many foreign leaders whose policies usually match those of the Democratic Party profess themselves frustrated with the Carter White House and less ready to condemn a possible Reagan White House out of hand.

Cutting across all political allegiances and philosophies seems to be a bafflement with the American electoral process and a wonder at its results.

"I think it is very regrettable that at the most dangerous moment in East-West relations since World War II, the only political product that America can offer is Reagan in exchange for Carter, even though there are undoubtedly lots of talented people in the country," Pierre Lellouche of the French Institute for International Ralations said.

A Guatemalan coffee grower said, "What the United States needs is a leader. Is this the best you can do?"

Many Western Europeans are concerned about Reagan's lack of experience in foreign affairs and about the uncertainty over who his chief foreign policy advisers would be.

British officials say privately that they see Reagan as unknown and unpredictable and as lamentably inexperienced in foreign policy as Carter was at this stage four years ago.

Pierre Hassner, a prominent French policial scientist who is sympathetic to the United States, said: "I fear that in Reagan's vision of the world there is nothing but the Soviet Union. He takes the view that there wouldn't be any hot spots in the world if the Soviets weren't there to heat them up. My worst fears are for what he might do in Latin America. I'm afraid he would just send in the Marines."

West German Chancellor Helmut Schmidt, known to be no fan of Carter, has let it be known among friends that he would favor a renewed Carter presidency over a Reagan one. Many West Germans have expressed fears that Reagan's hard anti-Soviet line could threaten Bonn's ostpolitik -- the policy of relaxed dealing with the Soviet Union and Eastern Europe.

Madrid's influential El Pais, in an editorial at the opening of the GOP convention, dismissed Reagan as an "imitation John Wayne," and told readers that in the 1960s he "was close to the John Birch Society -- a parafascist organization."

This view of Reagan as Cold Warrior was shared until quite recently by China and the Soviet Union as well.

In March, for example, when Reagan's nomination prospects were still unresolved, Radio Moscow called him a "double-eyed reactionary . . . behind whose back stands the military-industrial complex of the West."

Yesterday the influential Literary Gazette, in a dispatch from Detroit by Vitali Kobysh, a senior Kremlin information official, declared hopefully that Reagan's arms-building program "by no means implies any refusal on his part to conduct talks with the Soviet Union."

In a clear effort to put the best light on the Republican nominee's campaign rhetoric, Kobysh wrote that "it also was hinted that Reagan's former right-wing views have under gone considerable change in recent years, but that in his election program he was fettered by commitments given to the ultraconservative forces that nominated his candidacy."

George Arbatov, the Kremlin's top U.S. affairs analyst, have have summed up official feelings in a recent interview when he said that Ronald Reagan said bad things but president Carter did bad things.

The Chinese press attacked Reagan by name on June 14, largely because of reports, later denied, that Reagan would reduce ties with Peking in favor of improving relations with Taiwan.

This week the official New China News Agency quoted at length, with apparent approval, the anti-Soviet planks adopted in the GOP platform and the People's Daily yesterday published an unusual, straightforward profile of Reagan by correspondent Wang Fei.

Wang discussed Reagan's "reddish cheeks and shining black hair," which it said were signs either of good health or makeup, and he told his Chinese readership that Reagan's advisers tell people to watch "what he does, not what he says."

Many British officials from the perspective of more than a year under the conservative leadership of their own Prime Minister Margaret Thatcher, say that they think Reagan is more flexible than his public image.

Like Thatcher, they say, he may be staunchly uncompromising in his conservative ideology but a pragmatic politician when it counts. They see a lot of Thatcher in his views on both foreign and domestic issues.

Thatcher, ironically, has made it clear that she is very comfortable with Carter, although she refuses to be drawn out publicly on the issue of the U.S. campaign.

The Paris newspaper Le Figaro, the voice of French conservatism, in a full-page profile, concluded recently that the details of Reagan's program are unimportant since he is more pragmatic than he sounds but that his essential message is that of a strong-man who wants to rebuild America's muscles.

"But let's not have any illusions here," Le Figaro added. "Ronald Reagan is a strongman, but an old strongman."

India is another country that is making an effort to find something attractive in a Reagan who, in the view f its press and officials, is little known and lacks experience.

One point of his policy that pleases Indians in his view that the United States may be getting too close to China. India is trying to get close to China itself, but it fears the possible effects of a friendly axis among the United States, China and Pakistan.

In the Arab world, when Reagan's policies are generally condemned in the same breath as Carter's, one high Egyptian official said recently that he would love to see Ronald Reagan elected president because then at least Egyptian policymakers would be able to count on a steady line of U.S. policy -- not the zigs and zags that he said he found in the Carter administration.

But even with their doubts about Carter, most Egyptian officials, judging from conversations with reporters and press comments, do not look on Reagan as prsidential material, and they feel he would not have the same personal commitment as Carter to the U.S. promises made at Camp David.

In the large swath of the Arab world that opposes Camp David, Reagan is nonetheless viewed as a representative of traditional American political thinking and one who would follow a strongly pro-Israel policy if elected.

Many Israelis -- among them Moshe Dayan and Ezer Weizman -- have openly urged support for Carter's reelection and Labor Party leader Shimon Peres enjoyed telling Americans on a recent trip to Washington that he finds Reagan "as knowledgeable on the Middle East as I am on the Hollywood movie industry."

The prospect of Reagan as president poses a dilemma for many Israelis, particularly those outside government.

On one hand, an Israeli official said, Reagan is considered a firm anticommunist and thus an ideal candidate for unswerving support of Israel, which regards itself as a bastion of Western democracy in the Middle East. On the other hand he is considered an ally of big business, including big oil, and thus might moderate U.S. support of Israel to gain favor with the Arab oil nations.

In a mock presidential election at a fourth of July party in Johannesburg, open to Americans and South Africans, Reagan trounced Carter. In Reagan, white South Africans see a man who talks their language.

Reagan is seen not only as a cautious, anticommunist conservative, in the view of John Barrett, director of South Africa's privately funded Institute of International Affairs. He is also "seen as a realist. He's not talking of human rights as the basis for foreign policy."

Other South Africans are skeptical. One Afrikaans columnist wrote that "people who think Mr. Reagan could do something" for South African whites "really do not have much understanding of the intricacies of international politics."

Blacks in South Africa, and in the rest of Africa, have taken little interest in the U.S. campaign although some have expressed fears that U.S. ties would suffer if Reagan put the Soviet threat above all else in his relations with black Africa.

In revolution-wracked Latin America where the policy or caprice of the United States often has immediate consequences and ideological differences are frequently marked in blood, residents are watching the U.S. elections as if their lives literally depended on the outcome.

Rightists in bitterly divided El Salvador have advised their supporters to hold on until Reagan can come to their defense. Panamanians worry that a Reagan victory will jeopardize all they have won with the canal treaties.

Throughout Central America, liberals and leftists prefer a Carter victory while rightists, often stung by the Carter administration's human rights policy, declare they would rather see anyone than Carter in the White House.

Conservative Salvadoran demonstrators who recently tried to blockade the U.S. ambassador in his house carried placards calling for "Reagan for President."

Meanwhile in Iran, a country that could play a key role in influencing the American election because of its continued holding of 52 U.S. hostages, there seems to be little interest in who is elected.

Ayatollah Mohammad Beheshti, leader of the majority Islamic Republican Party in parliament, probably summed up official Iranian opinion when he said at a press conference yesterday:

"For us it's the same if this or that gets elected in the United States."