A senior Soviet official said today that Mikhail Gorbachev will attend the U.N. General Assembly session in New York in September, and the official raised the possibility of a summit meeting then between the new Soviet leader and President Reagan.

Viktor Afanasiev, editor in chief of the Soviet Communist Party daily Pravda and a member of the Central Committee, said in an interview with the Reuter news agency that it was his "personal view" that Gorbachev would meet with Reagan "during the General Assembly session" commemorating the 40th anniversary of the founding of the United Nations.

It was the first time that a member of the Soviet leadership has said that Gorbachev will go to the U.N. General Assembly session. Afanasiev, in an interview with the Yugoslav weekly newspaper Nin two weeks ago, had said he "believed" Gorbachev would attend it. But today he was quoted by Reuter as saying, "I know for sure that Mr. Gorbachev will go to the General Assembly session."

Reuter quoted him as saying that Moscow had agreed in principle to Reagan's summit proposal, "but it is hard to say when this meeting will take place." He added, according to Reuter, "My personal view is that probably this meeting will take place during the U.N. General Assembly session."

In Washington, State Department spokesman Ed Djerejian said "we have not received any official notification" that Gorbachev plans to attend the U.N. session, "and no arrangements have been made" for him and Reagan to meet. Djerejian said, however, that "there are many pressing issues in our relations with the Soviets, and we would naturally hope that any meeting between the president and Mr. Gorbachev would contribute to progress on the issues between our two countries."

Other Soviet sources, questioned about Afanasiev's statements, suggested that his views were "indeed personal" and that no decision has been made as to whether the new Soviet leader will meet Reagan. Soviet sources have indicated that such a meeting would be possible only if there is progress in the Geneva arms talks.

Afanasiev's statement today that Gorbachev will attend the U.N. session would indicate that at least that decision has been made.

Afanasiev frequently has caused controversy here by his outspokenness. In a conversation with Japanese editors late last year he described Gorbachev, who had not yet succeeded Konstantin Chernenko, as the party's "second secretary," or the second most powerful man, although there is no such title.

Earlier this year he said Chernenko was ill. At the time, Soviet spokesmen were saying Chernenko was taking his "winter vacation."

Afanasiev's interview with the Yugoslav weekly also made it clear that he is close to Gorbachev and that they have been working together on the text of the new Communist Party program.

As editor in chief of Pravda, Afanasiev holds a key position in the Soviet leadership, guiding the official party newspaper that daily enunciates the party line and serves as a guidepost to leaders around the country. Historically, the position has carried considerable weight: both Lenin and Stalin at one time in their careers served as Pravda editors.

Afanasiev emphasized today that a summit meeting would have to be well-prepared. "Some agreements should be signed. Compromises can be worked out. It's nonsense to talk about just meeting," he was quoted as saying.

In his response to Reagan's recent invitation to a summit meeting, Gorbachev reportedly had said that he welcomed "the idea of a summit" but that he had not addressed the questions of time and place.

Afanasiev, speaking to visiting Reuter executives, today praised the new Soviet leader, saying the country was "lucky" to have him.

In his conversations with the editors of Nin and the Yugoslav journal Komunist, Afanasiev said earlier this month that Gorbachev was an able man because he managed to get accepted to the law school of Moscow State University "without connections" at a time when there were 25 candidates for each slot available.

He said today that the next Soviet Communist Party congress, which uncharacteristically had been scheduled for next November, has been put off until next year. The date, he said, would be set at a meeting of the policy-making Central Committee on Tuesday. Before Chernenko, the congress traditionally had not been held until late winter or early spring.

* Aliyev Urges 'Bold Steps' -To Aid Soviet Economy ---Washington Post Foreign Service

MOSCOW, April 22 -- Politburo member Geidar Aliyev today told a Kremlin rally that the Soviet Union needed to "make new decisions and take bold steps" in dealing with its economic shortcomings.

In a speech honoring the 115th anniversary of Lenin's birth, Aliyev gave a forceful rendition of the themes sounded by new Soviet leader Mikhail Gorbachev in his first six weeks in office.

Aliyev, like Gorbachev a protege of the late Soviet leader Yuri Andropov, dwelt on the need to hold party leaders accountable "not by phrases but by deeds."

He urged the country's economic managers to resist a fondness for giving orders without consideration for the people's needs and "not to be afraid to promote young people."

The last point is expected to carry through the ranks this year as the Soviet Communist Party elects delegates to the 27th party congress, now expected to be held early next year. The congress will determine the composition of the 300-member Central Committee, the core of the nation's leadership.

Aliyev, who rose through the ranks of the KGB state security forces and the party in his native Azerbaijan, made a name for himself attacking widespread corruption there. He is now one of three first deputy prime ministers.

In the traditional Lenin birthday speech, he touched on the need to improve the Soviet economic performance, citing the coal, chemical, steel and railroad industries.

He called for a "rational use of wages, prices, cost and profit" in managing the Soviet Union's centralized economy. He also called for better efforts in the service sector, which, he said, should meet the needs of the people it serves, not the people who work in it. Managers who fail to meet standards of competency and moral responsibility should be moved out, not simply moved to other jobs, he said.

The stress on accountability by the leadership, on better use of existing resources and on greater independence for local managers has been sounded by Gorbachev, too, and in newspaper articles appearing since he became party leader on March 11. The same themes were first stressed by Andropov.

On foreign affairs, Aliyev emphasized cooperation with Moscow's socialist allies and accused the United States of aggravating world tensions with the pursuit of an arms race.

The Soviet Union and China said Monday that they want to increase political, economic, scientific and other ties, Tass reported, according to Reuter. The declaration followed a meeting between Soviet Foreign Minister Andrei Gromyko and Qian Qichen, head of a Chinese delegation visiting Moscow for talks aimed at improving strained relations.