Washington — Both sides have pronounced themselves pleased with the way the talks went between President Reagan and China's visiting Premier Zhao Ziyang. Mr. Zhao's meetings here over a three-day period with Mr. Reagan and other top American officials brought the United States and China closer to an agreement on peaceful nuclear cooperation, officials said.
The two sides also signed a new agreement on industrial and technological cooperation and extended an accord on science and technology exchanges. At a signing ceremony in the East Room of the White House Thursday, the President said, ''We're delighted with all that has been accomplished as a result of Premier Zhao's visit. His trip has solidified the goodwill between us.''
''The signing symbolizes that we should preserve what we have already achieved and open up new areas in bilateral relations,'' said Zhao. ''It shows that there are broad vistas for the development of US-China relations.''
''Let us continue our efforts to achieve new successes in our cooperation in the technological and economic fields,'' the Chinese premier said.
Reagan noted that China is engaged in a ''vast modernization program'' and stated that American know-how and investment should prove ''invaluable'' to its industrialization efforts.
Reagan acknowledged that there were still some differences between the two nations, but declared that they were committed to the same goals of peace and stability.
The two sides now look to a series of additional visits and meetings which might further consolidate the relationship:
* A possible visit to Washington as early as March of this year by China's Defense Minister Zhang Aiping.
* A joint US-China economic commission meeting in Peking on March 19, with Treasury Secretary Donald Regan heading the US delegation.
* Reagan's visit to China in April.
The chief disagreement between the two sides remains the Taiwan question. During the talks here, both sides restated their long-standing positions on the issue. But some experts say that Premier Zhao helped to defuse tension over that issue by finding a formula for saying that China had no objection to statements by Reagan that he wants to remain faithful to friends on Taiwan.
In an interview on Wednesday with Washington Post editors and reporters, Zhao said that being friends with people is a ''totally different conception'' from relations between states. He said that ''China always keeps faith and never forgets its old friends, but we never place such friendships above relations between states.''
''It is not right to interfere in a country's internal affairs merely for the sake of old friends,'' Zhao said.
On another touchy issue - the question of the divided Korean peninsula - the two seemed to find some common ground. On Wednesday, North Korea proposed in a radio broadcast that it join the US and South Korea in three-way peace talks. It was the first time that North Korea has endorsed the idea of peace talks to include the South Korean government.
Both Zhao and Reagan made tentative statements to reporters Wednesday welcoming the idea of talks, but Reagan indicated that he would favor a four-way meeting which would include China. South Korea rejected the proposal, insisting that before talks could begin, North Korea should apologize for the bombing in Rangoon, Burma, on Oct. 9 that killed 21 persons, including several leading South Korean officials.
At a briefing for reporters on the Zhao visit on Thursday, a senior administration official said in response to a question concerning Korea that ''it is certainly our impression that the Chinese are seriously looking for ways to reduce tensions in the Korean peninsula, as are we and as is the South Korean government.''