Vernon A. Walters, new U.S. ambassador to the United Nations, moved yesterday to replace Jeane J. Kirkpatrick's top U.N. staff with a team that includes a former colleague from the Central Intelligence Agency.

Herbert S. Okun, 54, a career foreign service officer who has served as U.S. ambassador to East Germany and as an arms negotiator, will succeed Jose Sorzano as Walters' deputy, the White House announced. Hugh Montgomery, 61, a longtime CIA official and past director of the State Department's Bureau of Intelligence and Research, was nominated to succeed Harvey J. Feldman as alternate U.S. representative for special political affairs.

President Reagan also said he will nominate career Foreign Service officer Patricia M. Byrne, 60, to be deputy U.S. representative in the U.N. Security Council, succeeding Richard Schifter. Finally, Reagan tapped New York banker Joseph V. Reed, his ambassador to Morocco, to replace Alan Lee Keyes as U.S. representative to the U.N. Economic and Social Council.

Reed, 47, was a vice president of Chase Manhattan Bank and an adviser to its chairman, David Rockefeller, when named U.S. ambassador to Morocco in 1981. He returned from that post in June.