Outgoing U.N. Ambassador Andrew Young is seeking a forum from which to maintain and expand his role as a national black spokesman on foreign and domestic affairs when he leaves the Carter administration, according to friends and advisers.

The 47-year-old minister, who submitted his resignation under fire last week, will probably move to Washington or return to Atlanta, acquaintances said, and establish a think-tank style office staffed by about half a dozen of his closest aides.

"Andy wants to remain a public figure, both domestically and internationally. If there is a new national black leader, it's Andrew Young," said a lawyer involved in the discussions about Young's future.

Young has ruled out running next year for the Senate seat held by Herman E. Talmadge (D-Ga.), as he was reported to have said last week he was tempted to do, sources said. Young does not believe a black can be elected to the Senate from Georgia, one acquaintance said.

But Young does plan to campaign actively for President Cater's reelection, despite what many see as irreparable damage done to the Carter administration's standing among blacks by Young's departure.

The sources cautioned, however, that Young, one of the blacks closest to the president, realizes he would need some strong commitments to blacks from Carter to offset opposition toward the administration.

"There's no question about his commitment to support Carter," one source said. "The question is what is Jimmy going to put on the table to give Andy some credibility."

Several People who have talked with Young said he believes the momentum establsihed toward changing the government during Carter's first four years must be continued.

"Andy said he believes that a second term Jimmy Carter is better than a first term whatever," said D.C. Mayor Marion Barry, who, along with several other black mayors, talked to Young soon after the resignation was announced.

The form of the organization that would be Young's base when he leaves his post next month has yet to be determined. The general scope of the effort was outlined by Young yesterday morning in New York at a breakfast with friends, aides and other blacks in the administration, sources said.

Young and his advisers hope to be able to attract enough financial support perhaps in the form of grants from private foundations -- to pay Young's salary and that of a staff to research and produce materials for him. Some of the money would pay for national and international trips, the sources said.

Young does not plan to set up a civil rights organization like the Southern Christian Leadership Conference, the Atlanta-based group he once headed, or the NAACP, sources said. Nor, they said, would his be a full-fledged policy think tank like the Brookings Institution or the black-oriented Joint Center for Political Studies.

Young's new office would be a more long-term effort, friends said. His immediate concerns are with winning what he is said to consider a pitched battle with the State Department over the reason for his departure.

State Department officials have linked Young's departure to what they say was an inaccurate and misleading account Young gave -- and later reversed -- about his meeting July 26 with Zehdi Labib Terzi, the Palestine Liberation Organization's observer at the United Nations. For several years, U.S. officials have promised Israel that they will have no substantive contact with the PLO, which is publicly committed to Israel's destruction.

Those who have talked with Young said he believes that the version of his explanation that the State Department released to the public was not what he told thedepartment. The implication by State that Young had resign because he lied has aroused Young's ire, they said.

"Andy has a strong sense of personal integrity. He resents the way they orchestrated it publicly," said one friend who attended yesterday's breakfast. "He's as angry as Andy can get. Andy does not usually express hostility."

National Black leaders have rallied in support of Young, and nearly 200 of them assembled in New York yesterday at a meeting that some said was unprecedented since the 1963 march on Washington because of the number of black leaders who took part.

There also has been sharp debate over a possible breach in relations between blacks and Jews because of Young's resignation, and some black leaders have discussed shifting their foreign policy stand to one more in favor of the PLO.

Young is said to be disturbed about a possible black-Jewish rift. But, sources said yesterday, he is happy that his departure has prompted increased discussions in this country about the question of the PLO's role in the Middle East conflict.