PHILADELPHIA (AP) _ The Rev. Jesse Jackson on Sunday hailed a Black Student Unity Conference here as the most significant since 1960, when the Student Non-Violent Coordinating Committee helped launch the civil rights movement.

''Your purpose means justice in America and peace in the world,'' he said, closing the four-day meeting of some 500 black college students from across the country. ''You are a source of joy to me.''

The conference, held at the University of Pennsylvania, drew Stokely Carmichael and Bobby Seale. Carmichael, who moved to Africa in 1969 and adopted the name Kwame Toure, was a founder of SNCC. Seale was a leader of the Black Panthers.

The meeting was to have featured controversial Nation of Islam leader Louis Farrakhan as the keynote speaker, but he canceled when the university refused to allow body searches of the audience and other security measures.

Students nevertheless said the conference was an inspiring event. It laid the groundwork, they said, for a resurgence of the black liberation movement.

Dereic Dorman, 21, a senior from Oberlin College and a conference organizer, said: ''We as black students are the vanguard. We are the leaders of tomorrow. We have a responsibility to take that leadership seriously,'' he said.

''It's made a closeness between all of us,'' said Aurora University student Cicely Killingsworth, 20, of Chicago, Illinois. ''To let us know that we are not alone. That we're coping in the United States and we can make it.''

The workshops and speeches fired her sense of pride and her determination to fight for better economic and social conditions for blacks, she said. Before, she believed she could accomplish nothing by talking about being a black American, she said. ''Now I don't feel I have to hold back.''

Jackson, a longtime civil rights leader who was a contender for the 1984 Democratic presidential nomination, exhorted his listeners to pursue an education, to take a political stand and vote, and to take ''moral living'' more seriously.

''Say no to drugs, say no to babies making babies and say no to violence,'' he said between bursts of applause. ''If someone can convince you to be selfish, to be cynical, to sniff drugs, you can't help the equation.''

Not all those attending voiced Jackson's unequivocal praise for the conference.

Conrad Tillard, president of the Black Student League at Penn, called Penn's refusal to allow searches a ''virulently, vehemently racist move ... that was calculated to block the appearance of Mr. Farrakhan.

University spokesman Virgil Renzulli denied the charge, saying the demand to search the audience would have constituted a violation of personal privacy.

Tillard said the security was needed because Farrakhan's appearance drew death threats.