WASHINGTON (AP) _ Business groups Thursday praised a federal appeals court ruling as a crippling blow to the concept of comparable worth, while labor unions and feminist leaders said they would continue to fight for the pay equity idea in collective bargaining, legislation and the Supreme Court.

The decision by the 9th U.S. Circuit Court of Appeals in San Francisco on Wednesday ''makes our efforts (on the pay equity issue in Washington state) a little harder and a little tougher,'' said Gerald W. McEntee, president of the American Federation of State, County and Municipal Employees, said Thursday. ''We recognize it as a setback.''

The union will appeal the ruling to the Supreme Court and ''we believe that we have both the law and equity on our side,'' McEntee told a news conference.

In contrast, Virginia Lamp, a labor relations attorney at the U.S. Chamber of Commerce, said ''comparable worth is an idea with superficial and political appeal, but which is now legally bankrupt'' because of the court decision.

Comparable worth, also known as pay equity, is the concept of paying men and women similar wages for different jobs judged to be of similar value to an employer.

Seven bills have been introduced in Congrees to introduce comparable worth to the federal government or private industry.

In reversing the nation's first comparable-worth court ruling, a three- judge appeals panel in San Francisco said employers can use prevailing market condition in setting wages, and need not follow surveys they commission.

In 1983, U.S. District Judge Jack Tanner in Seattle held the state of Washington liable for damages to 15,500 of its employees after a study commissioned by the state showed a 20 percent salary gap between workers in predominantly female and male jobs that required similar levels of skill, mental demands, accountability and working conditions.

But the appeals court said a wage gap, by itself, does not show that the state intentionally discriminated against women.

Despite the ruling, McEntee said that the union and Washington state officials have agreed to proceed next Monday with previously scheduled talks on a possible out-of-court settlement on the lawsuit, filed by AFSCME in 1982.

The union leader said he didn't think the decision had weakened union's bargaining position, adding that the Washington Legislature already has earmarked $40 million in its budget as a start to achieving comparable worth by 1993.

''I think the word is shock,'' McEntee said of his reaction to the ruling. But he stressed that more than 20 states have begun to conduct studies or have implemented some form of comparable worth.

About half of the rank and file in AFSCME, the largest union of public employees, are women.

The wages of working women nationally are just 68 percent of men's wages, the Labor Department says. The wage gap is closing, but not fast enough to quell the debate over comparable worth.

''We intend to break out of the ghetto of low wages ... one way or another,'' Eleanor Smeal, president of the National Organization for Women, said in a speech at the National Press Club.

Ms. Smeal said that under the free-market system cited in the appeals court ruling, ''you get away with discrimination if everybody else is doing it.'' But she added, citing child labor and collective bargaining laws, ''We decided long ago that the free-market system was not going to have no encumbrances.''

Many saw serious repercussions from the ruling.

With labor unions marching with women's groups on the issue, ''I think right now the (appeals court) decision will hurt union organizing efforts,'' said Ms. Lamp of the Chamber of Commerce. ''It's both a legal and political setback for the unions.''

''Courts have now unanimously affirmed that the essence of civil rights is equal opportunity for women, not comparable worth,'' said Chamber of Commerce president Richard Lesher.

The Washington state decision will be damaging psychologically because employers will use the ruling to avoid taking action on the issue, said Iowa state Rep. Minnette Doderer, who was instrumental in getting comparable worth legislation passed covering Iowa state workers.

Businessmen will say, ''See we don't have to pay women equally with men because they're not worth as much because they're women,'' said Doderer, who called the ruling ''a disgrace.''

''We have to litigate, legislate and agitate at the bargaining table,'' AFL-CIO spokesman Rex Hardesty said. ''Of course, a setback on any prong is serious'' for unions as well as for women, he conceded.