A nationwide program to repair the fraying alliance of blacks and Jews was launched yesterday by leaders of the NAACP and the Union of American Hebrew Congregations.

"The traumas which our communities sustained in recent years are in the process of being overcome," said NAACP President Benjamin L. Hooks and Rabbi Alexander Schindler, president of the UAHC, in a joint statement read at a press conference here. They pledged renewed cooperation "on the urgent issues which threaten civil rights and social justice in America."

Hooks and Schindler outlined a program of black-Jewish cooperation, both nationally and locally, on issues ranging from South Africa's apartheid policy to "economic justice" legislation.

The program specifically pledged "strong support for affirmative action," one of the stumbling blocks on which the strong black-Jewish alliance began foundering a decade ago.

Yesterday's announcement ended a two-day conference at the 4-H Center in Chevy Chase, where representatives of the two organizations discussed differences between blacks and Jews.

The effort, said Schindler, who heads the organization of Reform Judaism, was "not to bury our differences, not to ignore our differences, but to reduce them to the proper size."

Hooks and Schindler said in their statement that both groups are concerned about "the destruction of social programs by the Reagan budget, the attempted dismantling of civil rights enforcement by the U.S. Justice Department, threats to separation of church and state, the security of the State of Israel and the desperate need" for jobs for minority youth.

The two groups found common ground in their opposition to Reagan administration policies, from the visit to Bitburg to the "systematic effort of the Justice Department to unravel civil rights enforcement," leaders said.

The conference discussed a variety of programs to involve blacks and Jews, including interracial seders and joint Jewish and black worship services. The conference also heard about a Black Business Fair run by a Milwaukee synagogue; a joint campaign in Redding, Calif., against hate literature directed against both groups; and a cooperative store and community center in the multi-ethnic Crown Heights section of Brooklyn, N.Y.

Hooks also said that the NAACP intends to renew its drive for white membership. He said that Jewish membership in the NAACP "is not near what it was 20 years ago." He attributed the exodus of whites from civil rights organizations in part to the black power movement of the early '70s which, he said, caused "a lot of hard feelings."