President Pieter W. Botha and Bishop Desmond Tutu, the black South African Nobel Peace Prize winner, met for the second time in just over a month today to discuss the state of emergency in their strife-torn country.

The talks, for nearly two hours in Botha's presidential office, appeared to have yielded no agreement on any substantive issues, as with an earlier meeting June 12, the day the emergency was imposed. The Anglican bishop, who is regarded as the foremost spokesman for black South Africans, is being heavily citicized by blacks for the meetings, which they say give Botha credibility while gaining nothing in return.

Meanwhile, another clergyman who is a leader of the black commmunity, the Rev. Allan Boesak, said in Cape Town that he intended to take legal action against authorities for an incident yesterday. Boesak said armed police confronted him during a church service, then fired a tear-gas canister into his car.

In the talks, Tutu said he urged the president to lift the state of emergency and legalize outlawed black political organizations. Botha said he told the bishop, an advocate of sanctions against South Africa, that he expected him "as a South African" to oppose foreign intervention in the country's affairs.

Tutu said that Botha did promise to ask members of his Cabinet to investigate specific cases raised by Tutu involving political detainees and the harassment of clergymen.

Some analysts said today's meeting, coming at a time when the South African government is restricting blacks on a massive scale, would seriously damage Tutu's image among the young militants who are in the forefront of the antiapartheid campaign.

"He does it because as a Christian leader he feels he must, but I fear that by now he may have lost all influence with the young militants," said black leader Zwelakhe Sisulu, who was released last Friday after three weeks' detention under the sweeping emergency regulations.

What young blacks resent, said Sisulu, is that Tutu's meetings give a false impression that the government is prepared to talk to the real leaders of the black community.

For five years after their first meeting in 1981, Botha did not see Tutu and snubbed him several times when he sought meetings. Now, Sisulu feels, the government has decided these meetings are useful to its image abroad with nothing being yielded.

Tutu is aware that the meetings have hurt him politically and that they have achieved little. He was philosophical when asked in an interview tonight whether he thought they had been worthwhile.

"There are a lot of minuses, I know, and I end up scratching around trying to find pluses," he said.

Tutu said he sought today's meeting at the request of his church council, which asked him to try again to intercede with the president. "We have bishops and priests who are in jail. I can't just sit there and do nothing," he said.

Botha said he told Tutu that the emergency was necessary to reestablish law and order, which had broken down after a previous state of emergency was lifted last March. He said that since its reimposition, a greater sense of safety had returned to the black townships and economic faith in the country was recovering.

Tutu later held a 15-minute meeting with Constitutional Affairs Minister Chris Heunis, in which Tutu said he urged restraint in dealing with rent boycotters in black townships.

Boesak, who is president of the World Alliance of Reformed Churches, said in an interview in Cape Town today that he was overcome by gas when authorities fired the tear-gas canister into his car last night.

The incident followed a confrontation with armed police in a church where Boesak was preaching in the mixed-race township of Elsies River, outside Cape Town.

He had just begun addressing the congregation, Boesak said, when armed riot police surrounded the building and a captain accompanied by several armed men came into the church and ordered him to stop preaching.

The captain grabbed a microphone and the two struggled over it until it broke, Boesak said. The captain then left the church to call a superior officer, telling the congregation of about 200 that they were "technically under arrest." According to Boesak, a policeman with a gun remained beside the pulpit while he continued preaching for the next hour and a half.

The congregation then was allowed to go. As it left, Boesak said, two canisters were fired from a tear-gas launcher. One smashed through a window of his automobile and he was overcome by the gas.

Ronelle Henning, a spokesperson for the Bureau for Information, the only authorized source of news under the emergency, said police entered the church after receiving information that an illegal meeting was being held there. Henning said the police fired tear gas when some of the people began stoning them and one policeman was injured.

Free-lance reporters in South Africa contributed to this report