Andrew Young, former U.S. ambassador to the United Nations, encountered apathy and some antagonism as he campaigned here today in behalf of President Carter.

Young was personally well received, but his defense of the Carter administration evoked only lukewarm response in speeches before two predominantly black audiences.

Young insisted that the Carter candidacy "is not the lesser of two evils." In case there were doubters, the longtime civil rights leader added, "the election of (Republican) Ronald Reagan will mean the rest of my life will be hell."

A Reagan presidency "would be a threat to the equal rights I have fought for for 25 years," Young said.

A Supreme Court filled with appointees of former president Richard M. Nixon and Reagan "would run this country for 20 years, affecting our lives and those of our children and of our children's children," Young said.

At a luncheon to which 100 black elected officials and labor leaders had been invited -- but at which only 50 showed up -- Young cited 10 reasons that blacks have in Carter "a president we can vote for."

Among those reasons, he said, were expansion of the food stamp program, increases in the minimum wage, cost-of-living adjustments for social security recipients, extension of unemployment benefits to 52 weeks, the inclusion of Africa in U.S. foreign policy and the appointments of 41 new black federal judges and 170 blacks to decision-making positions in the administration.

When several persons in the audience questioned Carter policies, Clarence Mitchell Jr., a veteran Washington representative of the NAACP, who was at the speaker's table with Young, rose and spoke in anger.

"I'm sick and tired of blacks looking for excuses not to vote for Carter," Mitchell said. "If Ronald Reagan gets in the White House, everybody's going back on the plantation."

After the lunch, Baltimore council vice president Clarence (Du) Burns predicted that Carter again will carry Baltimore's black precincts by the 5 to 1 margin he did in 1976.

"We don't have a choice," Burns said.

In a speech at Morgan State University later in the day, Young talked about the administration's jobs program. He was interrupted by one student who yelled, "Forty percent of the guys in this town don't even have a job. What are you talking about?"

Young answered that "I don't support the administration policy that fights inflation by increasing unemployment . . . we can make Jimmy Carter a great president, whatever his limitations."

Young also was asked, "How can you support Carter when he forced you to resign?"

Young responded that "it was my decision to resign" as U.N. ambassador. He said he acted quickly when he became the focus of a dispute over Middle East policy because he wanted to avoid a split in the traditional liberal alliance between blacks and Jews.

He said he knew he was violating formal U.S. policy when he met with representatives of the Palestine Liberation Organization, "but I did it because I thought it was necessary" as a step toward a final Middle East peace settlement.

Speaking at the dedication of an urban park on the eastern edge of Baltimore's revitalized downtown, Young said he agrees with the president's decision to boycott Sunday's presidential debate in the convention center here.

He said the League of Women Voters adopted "a naive liberal formula" in inviting Independent John Anderson to participate in the first of the nationally televised meetings of the presidential candidates.

Asking Carter to debate two Republicans is "like asking Muhammad Ali to fight both Weaver and Tate at the same time," said Young, quickly adding, "although neither Reagan nor Anderson are heavyweights."

Young said Carter might win a three-day debate "but lose the presidency." He explained that giving Anderson equal status "might get him an additional 5 percent" of the vote on Nov. 4, "just enough to elect Reagan."