The Supreme Court, delivering another setback to the women's movement, yesterday ruled that a military wife has no right to share her ex-husband's pension after a divorce.

Though recognizing that the "plight of an ex-spouse of a retired service member is often a serious one," the court said the money belongs only to the one who served.

The 6-to-3 ruling directly affects only the military. But it took on great significance to the women's rights movement because feminists have sought judicial recognition of a woman's often unpaid contributions to her family.

The decision in McCaty v. McCarty was the second major defeat in two days for feminists. On Thursday, the court allowed the exclusion of women from the military draft. It is further evidence, National Organization for Women President Eleanor Smeal said in a second angry statement, of why a woman should be appointed to the court.

Yesterday, the court cited its reasoning in the draft case -- deference to Congress on military matters -- to justify its latest decision. Congress, Justice Harry A. Blackmun said for the majority, intended the military pension to belong to the ex-soldier. The courts may not override that. ". . . In no area has the court accorded Congress greater deference than in the conduct and control of military affairs."

The ruling also hurts civilian men who are divorced from women in the military. But at the moment, there are relatively few in that situation.

In the draft case, said Women's Legal Defense Fund lawyer Judith Lichtman, the court implied that women were "too important to the family" to be drafted. "Today, it says a woman's worth at home counts for nothing . . . . It puts us in a classic no-win situation."

Richard John McCarty, an Army doctor holding the rank of colonel, separated from Patricia Ann McCarty in 1976. Their divorce proceeding took place in California, where the divorce laws treat everything bought or earned during a marriage as "community property" to be divided between a couple. Seven other states have similar laws.

As a result, the California courts gave Patricia McCarty a share of her husband's military retirement pay, which he was to start receiving two years from the date of the divorce after 20 years of military service.

Feminists argue that retirement pay belongs as much to the wife as to the working husband. A woman's work at home, often as a mother, makes her an equal partner making an equal sacrifice in her husband's career, they say. Both the Civil Service and Foreign Service retirement laws have recently been changed to allow sharing in the event of a divorce. A similar proposal for military pensions is pending in Congress.

But until such an amendment is enacted, the court ruled yesterday, the money is the exclusive property, the "personal entitlement," of the spouse who officially earned it.

Blackmun said the retirement pay law for the military was designed by Congress for several specific reasons: it was a personnel tool to encourage older soldiers to retire and create a "young and vigorous" military force; a way to ensure orderly and regular promotions in the military; an incentive for people to join the military and reenlist, and a way to provide for retired personnel.

All of these purposes would be frustrated by a soldier's knowledge that the pension is not his exclusive property, he said: sharing would "frustrate" the purposes of the federal law.

State divorce laws may not override federal law, Blackmun said. ". . . This decision is for Congress alone."

Justice William H. Rehnquist, who wrote Thursday's draft ruling, wrote a dissent yesterday along with Justices William J. Brennan Jr. and Potter Stewart. Rehnquist said that Congress did not explicitly say that the pension law should override state divorce laws. The majority thus has interfered with "matters of peculiarly local concern," family and property.