WASHINGTON (AP) _ President Bush today credited the Soviet Union with ''definite improvement'' in human rights but said the United States will watch what develops in the months ahead while weighing whether to carry through with a promise to attend a Moscow summit on human rights in 1991.

''I think we need to look for performance, and there will be time in which to see performance in that regard,'' he said. He added ''there has been definite improvement in some ways there, but let's see what develops as we move towards that conference date.''

White House spokesman Marlin Fitzwater said Bush was not backing away from its commitment to attend the Moscow conference but said, ''There's plenty of room for independent analysis'' between now and 1991.

Bush made his comments in an interview with two reporters as part of a White House's experiment to make the president available to the news media in different forums. A transcript of the session was made public.

The president hinted he may visit China next month after stopping in Japan for the Feb. 24 funeral of Emperor Hirohito. ''Stay tuned,'' he said. ''We may have something on that ... yea or nea before the close of business today, but I just don't know yet.''

There also is speculation Bush will visit South Korea while in the Far East.

On other subjects, Bush said:

-He does not want the Federal Reserve Board to act too strongly to bring down inflation rates. Fed Chairman Alan Greenspan said Tuesday that inflation was too high and he would press to reduce it.

While noting that he had not talked with Greenspan recently, Bush applauded the upward movement in the stock market and said ''there's no signals out there in the markets that this economy is in real trouble. ... I don't want to see us move so strongly against fear of inflation that we impede growth.''

-The administration is considering imposing a fee on customers of savings and loan institutions to help the federal government pay to insure the troubled S&L industry. ''That's one option,'' he said, adding that the idea had not been presented as a formal recommendation. ''And so I'm not going to say what I'm going to do but that is one option.''

-He is not considering dropping Dr. Louis W. Sullivan as his candidate to head the department of Health and Human Services. Sen Gordon Humphrey, R-N.H., said some senators who have met with Sullivan report that the nominee personally supports the Supreme Court decision that legalized abortion - a view different from that of Bush, who says he wants the decision reversed.

However, Bush said, ''He has supported my position 100 percent.''

-He favors ''prudent development'' by oil companies in a vast Arctic national wildlife refuge. Environmentalists are trying to enlist Bush's support to keep the oil companies out, and say it the issue will be a litmus test on how much Bush really wants to protect the environment.