President Carter said yesterday allegations that American Jewish leaders "urged me to ask" U.N. Ambassador Andrew Young to resign are false.

Speaking at the White House swearing-in ceremony of Young's successor, his former second-in-command Donald McHenry, Carter said that Young "made his judgment on what was best for the country and him."

Many Jews had been doubly dismayed last month when, first, blacks had blamed Jewish organizations for Young's resignation and, then, Carter had ignored repeated requests by the Jewish community to say publicly that it was not responsible. The controversy was stirred up when it was disclosed that Young met with a representative of the Palestine Liberation Organization in New York last July. Last month Young announced his decision to leave the U.N. post after 2 1/2 years.

"Any claims or allegations that American Jewish leaders or anyone else urged me to ask Andy for his resignation are absolutely and totally false," Carter told a largely black audience. His remark was greeted with applause.

Earlier yesterday, Young said on "Issues and Answers" (ABC, WJLA) that he does not expect Sen. Edward M. Kennedy (D-Mass.) to challenge the president for the nomination next year.

"I don't think Senator Kennedy will take the black vote against President Carter because I don't think he's going to challenge President Carter. . . . A fight over the black vote in the Democratic Party will jeopardize anybody in the run for the general election. I think Senator Kennedy is too smart for that," Young said.

At the swearing-in, Carter called McHenry a "foreign policy professional" who would continue Young's work. Young, Carter said, is "my friend and a friend of the world."