INDIANAPOLIS (AP) _ Decisions striking down an ordinance that defines some pornography as a violation of womens' civil rights may be appealed to the U.S. Supreme Court, the city attorney said.

But an anti-pornography activist said appealing the federal court ruling Tuesday that characterized the ordinance as a form of thought control would likely waste city funds better spent on enforcing existing laws.

''We felt all along that the laws already in place are good enough,'' said Phillip Nine, vice president of Citizens for Decency through Law, a group that has picketed adult businesses. ''We feel that the primary problem is in the courts. It's a problem of getting them to uphold the law.''

The measure, modeled on a similar ordinance drafted in Minneapolis and vetoed by Mayor Don Fraser in January 1984, was ruled unconstitutional Tuesday by a three-judge panel of the 7th U.S. Circuit Court of Appeals in Chicago. The panel affirmed a Nov. 19, 1984 ruling by a federal judge in Indianapolis.

Under the ordinance, the appeals court wrote, ''Speech that 'subordinates' women ... or even simply presents women in 'positions of servility or submission or display' is forbidden, no matter how great the literary or poltical value of the work taken as a whole.''

Speech that portrays women in positions of equality, the panel wrote, ''is lawful, (under the ordinance) no matter how graphic the sexual content. This is thought control. It establishes an 'approved' view of women...''

City Attorney John P. Ryan said officials would study the decision before deciding whether to appeal. ''It's very likely we'll ask the Supreme Court to look at it.'' Such an appeal could take up to two years, Ryan said.

''We're very disappointed,'' he said.

Beulah Coughenour, who introduced the measure in the Indianapolis City- County Council, said, ''I don't think we really expected the 7th Circuit Court to change the constitution and that's what we're trying to do here, is carve out another exception to the First Amendment.''

Six trade associations representing book and magazine publishers and distributors challenged the measure May 1, 1984 - the day it was signed into law.

''History teaches us that when the censor begins, he or she is never satisfied,'' said Burton Joseph, the plaintiffs' attorney. ''No one's right to free expression can be protected unless everyone's is, including expressions of others that we find offensive or even hateful. That's what the First Amendment is designed to protect.''

In writing the opinion for the appellate panel, Judge George Easterbrook questioned how the Indianapolis ordinance would treat works ranging from James Joyce's ''Ulysses'' to Homer's ''Iliad.'' Both, he said, ''depict women as submissive objects for conquest and domination.''

In its appeal to the 7th Circuit, the city considered the possibility the lower court ruling would be upheld and asked the appellate judges to indicate those parts of the ordinance that could be held constitutional.

''We would hope that the opinion would give us some direction on how to correct that which the court thinks is incorrect,'' Ryan said Tuesday night.

He said the city now attempts to regulate adult businesses through zoning ordinances and other laws. The number of massage parlors has been reduced by more than half with such enforcement, Ryan said, but the federal court decision leaves the city with little means to regulate printed and other sexually explicit material.

''I guess we we've put all our eggs in one basket with this ordinance,'' he said. ''The premise was pretty clear, that pornography subjugates women.''