The Soviet Union today portrayed former U.S. secretary of state Cyrus Vance as a dedicated advocate of detente forced out of power by an administration that has embraced "adventurism" in dealing with its adversaries.

Soviet national television said that Vance "had tried to put a brake on Washington's slide into a military anti-Soviet position." It said he suuported early SALT II ratification and continued detente with the Soviet Union, and opposed military sales to archrival China and "adventurist actions toward Iran."

The official Tass news agency in a brief dispatch from Washington also exposed strong Soviet fears that the Carter administration's foreign policy will now be controlled completely by national security adviser Zbigniew Brzezinski, whom the Soviets have long labeled a cold warrior.

"Observers are of the opinion that with Vance's resignation," Tass asserted, "Carter administration policy will be showing ever more manifestations of adventurism whose symbol Brzezinski is."

Despite triggering new worries over Brzezinski's expanded influence, Vance's departure also offers Moscow opportunities in its current efforts to persuade the West European countries that the Carter administration is dangerously unreliable. Televison newscaster Vladimir Dunayev reflected this theme, saying the resignation "will deepen the crisis between the U.S. and its allies, Vance was a man whom the U.S's partners regarded with respect and [as] as one of the few administration representatives who enjoyed authority as a moderate politican."

Tass noted that Vance resigned "with a heavy heart," in protest against "the adventuristic attempt" of the White House in ordering the abortive Iranian rescue attempt.

This sympathetic portrait, sure to be embellished in weeks ahead, leaves no room on the official canvas for sketching in the true state of relations that developed between Vance and the Soviet leadership over 3 1/2 years of meetings. In fact, the Soviets never have seemed entirely comfortable with the somewhat shy and lawyerly Vance.

Their reserve dates to his first mission here, in March 1977, when the fledgling Carter administration startled the Kremlin gerontocracy of Leonid Brezhnev with radically new strategic arms limitation proposals. The Soviets rejected them out of hand an it took months to get the SALT talks on track.

While the Soviets seemed to gain respect for Vance as a tough and thorough negotitator deeply committed to the SALT II process and detente, they clearly never felt the same rapport with him as with his predecessor, Henry Kissinger, who cultivated a personal relationship with Brezhnev. The Soviet suspected from the start of the Carter administration that Vance did not dominate foreign policy as Kissinger had.

Despite the conditioning of Communist Party leaders to respond to historical processes rather than individuals, Brzezinski always has drawn suspicious Soviet attention. One senior Soviet foreign policy adviser once described Brzezinski as "a member of the Polish Catholic nobility, hereditarily opposed to Soviet power."

It is a view that prevails here and with Vance gone, the Soviets can now devote their full attention to the best-known advocate of "playing the China card."

That prospect undoubtedly helped motivate the sympathetic picture of Vance.

From Paris, Washington Post correspondent Ronald Koven reported:

Vance's departure seems bound to increase West European anxieties about where Washington intends to lead the West in its relations with Moscow.

Vance was depicted by French sources as a "man of dialogue, willing to compromise," and this perception appears not to transfer to Brzezinski, in the view of French diplomats.

The newspaper Le Monde, regarded as the voice of the French establishment, wrote that "the perhaps final burial of [the SALT II] agreement and the rise in tensions with the U.S.S.R. seriously weakened [Vance's] position. . . . Mr. Brzezinski now has a free hand to impose the global and activist view he has of East-West rivalries, to which he has rallied the president."

Vance generally was admired in France and in Europe as a competent professional diplomat in the traditional mold that Europeans have been used to dealing with.

Le Monde lauded in Vance the "virtues of compromise rather than those of confrontation and which find repugnant such extreme measures as the unsuccessful raid on Iran."

Coming so soon after the hostage rescue raid, Vance's resignation seems bound to reinforce the opinion among many top Europeans that the United States is not a safe or responsible leader for the West. U.S. policy, these Europeans feel, is dominated by amateurs and people who favor an irrationally hard line toward the Soviets.

Washington Post Asia correspondent William Chapman reported:

The biggest effect of Vance's resignation is likely to be a reinforcement of the view that the Carter administration is erratic, inept and unpredictable.

Over the past week, as a hard line emerged in Washington on the Tehran hostages, Vance had been viewed in Tokyo as a restraining influence. His departure now seems likely to encourage fears that anything can happen and that the United States is more likely to seek military solutions.

Foreign Minister Saburo Okita initially condemned the rescue operation as "regrettable," and suggested that sanctions against Iran be reconsidered. He changed his mind after a call from Vance and accepted the action as a "humanitarian" mission, an indication of the respect with which Vance was held.

The state visit beginning Wednesday of Prime Minister Masayoshi Ohira is expected to take place in a less sympathetic atmosphere to Japan than would have been the case under Vance, Japanese officials feel.

Washington Post correspondent William Claiborne reported from Jerusalem:

Israelis see Vance's resignation as another blow to President Carter's international prestige, and that is a matter viewed here with concern.

Any decline in American global influence leads Israeli policymakers to worry that such substitutes as the European Community will fill the void, providing a tilt toward the Palestine Liberation Organization unacceptable to Israeli leaders.

Vance was viewed here as a champion of the Camp David peace process. Officials credit him with having played a key role in the initial Camp David talks and with an even more decisive role in getting the treaty signed.

Isreal is already concerned that the resignation will enhance Brzezinski's influence on U.S. foregin policy in the Middle East and policymakers expect more pressure on Prime Minister Menachem Begin in the stalled negotiations on Palestinian autonomy.

Begin expressed Isreal's "deep regret" over the resignation, calling Vance "a friend of Israel who wished to help our country."

Washington Post correspondent Jonathan C. Randal Added from Beirut:

Vance's resignation provoked fears in the Arab world that the United States is adopting a more muscular approach to Middle East problems, reminiscent of the dangerous oversimplifications of the cold war era.

There was general agreement among diplomats, politicans and analysts that Vance's real successor in U.S. foreign policy councils would be Brzezinski, who has raised hackles from one end of the Arab world spectrum to the other.

His dismissive "Bye, bye, PLO" remark to a French journalist -- whether accurate or not -- did little to endear him to the Palestine Liberation Organization. Nor did his March 1979 visits to King Khalid of Saudi Arabia and King Hussein of Jordan accomplish their purpose of winning those once solidly pro-American monarchs over to the U.S. engineered Egyptian-Israli peace.

Rightly or wrongly, Brzezinski was found wanting in Middle East expertise and especially for failing to understand that for Arabs of all political stripes -- indeed, for virtually all Moslem nations -- the Palestinian question and U.S. support for Israel were considered far more important.

A respected Arab commentator lamented privately: "What do you expect can be accomplished in the Middle East when Brzezinski and Begin come from the same country?" Both were born in Poland.

Washington Post southern Africa correspondent Jay Ross reported from Lusaka:

The hawk-dove clash between Brzezinski and Vance did not reach Africa, a high State Department official said recently.

Nevertheless, Vance's resignation, together with that of the U.S. ambassador to the United Nations, Andrew Young, last year, means that the two leading exponents of Carter's policy on Africa are no longer in office. The administration had won friends in black Africa by moving the United States away from positions supporting white-minority governments.

Observers believe that Brzezinski's emphasis on East-West aspects of policy is likely to get more prominence with Vance out of the way. They feel that this is likely to mean a stiffening of opposition to African governments that house large contingents of Soviet or Cuban troops, such as Ethiopa and Angola have done.

Another outgrowth of Brzezinski's overshadowning of Vance is the expectation among observers that there probably will be even less publicly stated opposition to South Africa's policies of racial separation.