WASHINGTON--A much-publicized ordinance that would make distributors of pornography subject to sex discrimination lawsuits is unconstitutional, the Supreme Court ruled yesterday

The court, by a 6-3 vote, said the Indianapolis, Ind., ordinance impermissibly interferes with free speech.

The decision was announced without opinion. The court, without waiting to conduct oral arguments or solicit more briefs in the case, merely upheld lower court rulings.

Chief Justice Warren E. Burger and Justices William H. Rehnquist and Sandra Day O'Connor voted to hear arguments in the case, but four votes are needed to grant such review.

In seeking the Supreme Court's help, Indianapolis Mayor William H. Hudnut III and other city officials argued that the ordinance is an "innovative and promising" way to help victims, mostly women and children, of the pornography industry.

"The record shows that the pornography industry...generates sex-based abuse," the justices were told.

The ordinance was enacted by a 24-5 vote of the city council on April 23, 1984. It defined pornography as a practice that discriminates against women by portraying them as sexual objects who enjoy pain or humiliation and presents them as sexual objects of violence.

It allowed women injured by someone who had seen or read pornograhic material to sue the maker or seller of the pornography.

Even as the ordinance was enacted, its supporters voiced doubts whether it would withstand a legal challenge.

The American Booksellers Association, comprised of about 5200 bookstore owners, quickly challenged the ordinance in a federal lawsuit.

U.S. District Judge Sarah Evans Barker on Nov. 18, 1984, ruled that the ordinance violated free-speech rights. She previously had barred its enforcement.

The 7th U.S. Circuit Court of Appeals upheld her ruling last Aug. 27, stating that the ordinance wrongly discriminates on the basis of speech content.