Prime Minister Pieter Botha today criticized the Reagan administration's top African-affairs official for actions that appear to have dimmed Pretoria's hopes for improved relations between the two countries.

In an interview with the Johannesburg Star, Botha said he held Chester Crocker, assistant secretary of state-designate for Africa who is touring the continent, responsible for U.S. objections about the controversial visit last month of five South African military officials. He also said he was displeased by Crocker's refusal to regard a black African guerrilla movement fighting South African forces in Namibia (South West Africa) as a communist surrogate.

While Crocker was being publicly chastised here, leaders of six African nations meeting in Angola accused the United States of trying to overturn Angola's Marxist government, The Associated Press reported. In a joint communique the one-day summit assailed the Reagan administration for ""considering measures to destablize the legitimate government of Angola,'' an apparent reference to its efforts to repeal legislation that prohibits aiding anti-government guerrillas in Angola. rCrocker will travel of Angola Friday.

In a reflection of the racial tensions in the area, only seven hours after Crocker left, South African security police confiscated the passport of black Anglican bishop Desmond Tutu. Botha threatened last month to revoke the passport while Tutu, an outspoken opponent of the government's apartheid system was on a trip overseas.

Botha's remarks to the newspaper come during an election campaign, a period in which Afrikaner leaders traditionally take a tough stand against any U.S. government remarks that can be seen as pro-black. They also are in contrast to an assessment of the visit made by Foreign Minister Pik Botha, who met with Crocker, during his two-day visit here.

The foreign minister said tonight that talks, which lasted longer than expected, were "useful" and that he believed the Reagan administration was "more realistic" than the previous one. He said the prospects were improved now for successful negotiations for the independence of Namibia, a territory administered by South Africa. But he cautioned that "we are at the beginning of perhaps a series of further discussions. . . . There's still a lot of work to be done.

Crocker did not have any official business meetings with black leaders here, saying that his current African trip was limited to meeting goverment officials. But he met socially with Soweto spokesman Nthato Motlana and an official of the Zulu Motlana and an official of the Zulu Inkatha party, Gibson Thula, at a private dinner.

Before his departure today Crocker said his talks with the South Africans had been "a useful opportunity for us to exchange at senior levels our viewpoints from both sides. I think we understand each other's positions and views much more clearly than before."

Both the South Africans and the Americans refused to elaborate privately on the talks, which centered on a new Western diplomatic initiative to find a negotiated solution to the Namibian bush was. One participant, however, said the talks "went well."

Botha's explanation for why he declined to see Crocker came in a lengthy interview covering many topics that was clearly timed with an eye to the vote of conservative white English-speakers in the April 29 elections.

"I have certain reservations after Dr. Crocker's visit to Africa and even earlier," Botha said.

"I don't like the way he referred to SWAPO. I think it is an attempt to create an atmosphere in which he can talk to SWAPO's friends. Well it doesn't suit us, we don't like SWAPO.

"We know that SWAPO is communist-controlled and they have one idea and one idea only, and that is to subordinate South West Africa by brutal force. So I don't like his remarks so far."

On Monday Crocker said in Zimbabwe that "there is no question that SWAPO is supported by the Soviets and their friends at present, but I think it would be an oversimplification to think it would be an oversimplification to think that that by itself accounts for what SWAPO does or what SWAPO would do if it were to win an election."

That remarks was called "unfortunate" and being "soft on SWAPO" by the South African press.

Botha also said that before Crocker came to South Africa "he was responsible for the objections to the presence of Gen. [Pieter] Van de Wsesthuizen in America and that is not the way we are going to find each other. Either we go to America with self-respect and we are received there with respect or there are not going to be good relations."

Van der Westhuizen, who is head of military intelligence, and his four military colleagues, did not notify the American embassy here of their military ranks when they applied for visas. The United States has a longstanding ban on visits by South Africa military officials.

The officials left the United States after the State Department discovered their presence in Washington, and their method of gaining visas angered many officials. They met, however, with a member of the National Security Council and with U.S. Ambassador to the United Nations Jeane Kirkpatrick.

Tutu, an outspoken opponent of the government's racial apartheid system, angered Botha with his critical remarks about South Africa and his support for boycotts against this country while on a trip overseas.Botha announced while Tutu was in the United States that his passport would be withdrawn when he returned home. Tutu returned last Thursday.

Tutu said the withdrawal of his passport "won't deter me from doing the things which God has called me to do. It will do nothing to alter my attitude or stance or hinder our liberation process."

"I feel sorry for the prime minister," he said. "He is a pathetic little bully. He is not man enough to admit he had made a mistake. He needs to be prayed for.

"Why are they frightened of little me? I don't have the vote. They spend millions on propaganda overseas; why should they be frightened of what I say? Or did they think I was going to upset the applecart of the romance they were building with the Reagan administration?"