PHILADELPHIA (AP) _ Cardinal John Krol celebrated his 25th anniversary as leader of the Archdiocese of Philadelphia on Sunday, calling for a renewed effort against abortion, birth control and homosexuality.

Speaking to an estimated 8,000 people who attended his silver jubilee Mass, Krol warned against secular humanism - the belief that man should act as though God does not exist.

''It's a religion without a God,'' said Krol, who has led the 1.35 million Roman Catholics in the archdiocese since Feb. 11, 1961.

''Abortion, homosexuality, pornography and even the drug culture - it's rationalization according to the need of the individual,'' he said. ''We must energize our society with the light of Christ and of this Gospel.''

The official archdiocesan salute, held at the Philadelphia Civic Center, was attended by a number of lay and clergical dignitaries from across the country who paid homage to Krol, long-recognized as one of the leading conservative leaders of the Catholic church.

Thunderous applause, and a few whistles, greeted Krol when he stepped into the hall, which was ringed with red and white banners bearing the names of each parish within the archdiocese, the sixth largest in the country.

Krol followed a 25-minute procession of seminarians, priests and bishops who walked under a saber honor guard provided by the Knights of Columbus, a Catholic men's group.

Five of Krol's fellow cardinals - John Dearden, the retired leader of the Detroit archdiocese, Joseph Bernardin of Chicago, Bernard Law of Boston, John O'Connor of New York and William Baum of the Vatican - joined him in con- celebrating the Mass.

Busloads of Catholics, including many children in their parochial school uniforms, from parishes across the archdiocese participated in the celebration.

Krol's brother, Alfons Krol, former Mayor Frank Rizzo and Police Commissioner Kevin Tucker were among the front-row guests.

''It's a historical occasion,'' said Robert Klecko, 40, of Chester. ''I was in high school when he first came here, and I thought I wanted to be here for his big day.''