The Supreme Court agreed yesterday to review an issue of major importance to Indian tribes: whether their sovereign right to determine who their members shall be must give way to the promise of equal protection of the laws in the Indian Civil Rights Act of 1968.

The issue arises from a challenge to a ruling by the Santa Clara tribe in New Mexico that the children of mixed marriages become tribal members if their father is a Santa Claran, but not if their mother is. The Tenth U.S. Circuit Court of Appeals ruled that this action deprived the children of female Santa Clarans of equal protection.

The court took other actions: CONGRESSIONAL PAY

Congress has been giving itself pay increases by letting recommendations for them by a special commission and the President go into effect without a vote by the House and Senate. Contending that the procedure is unconstitutional, Rep. Larry Pressler (R.S.D) used to stop it.

Last October, a panel of three federal judges here dismissed his complaint. In April, Congress amended the procedure to require a vote on future raises. Yesterday, the court sent the case back to the panel "for further consideration in the light of the new legislation." RIGHT TO HOLD OFFICE

E. C. Chappelle Jr. won appointment to the Greater Baton ROuge Airport Commission in 1974 - only to be removed from the unpaid post 10 months later under a Louisiana law requiring officeholders to be owners of proverty assessed in their parishes. The Louisiana Supreme Court rejected his challenge to the law's constitutionality. Yesterday, the U.S. Supreme Court, in an unsigned opinion, reversed. ILLEGAL CAMPAIGN CONTRIBUTIONS

In March, 1976, a federal grand jury indicted Claude C. wild Jr., formerly Gulf Oil Corp.'s Washington lobbyist, on charges of making two illegal campaign contributions: $5,000 to the 1974 re-election campaign of Sen. Daniel K. Inouye (D-Hawaii), and $2,500 to the 1972 campaign of Sen. Sam Nunn (D-Ga).

In July, a judge freed Wild in the Inouye case on the ground that the three-year statute of limitations ran out before the indictment was returned.

In the Nunn case, however, Wild, after consulting with his then-counsel, Edward Bennett Williams, explicitly waived the statute only two days before it ran out in 1975, apparently in the hope that plea bargaining would spare him from prosecution.

A panel of three federal judges, in the first ruling of its kind, said the waiver was valid. Yesterday, the court let the ruling stand. Wild now faces the prospect of standing trial on the charge. DRIVERS' LICENSES

Does the Constitution require a preliminary hearing before a state can revoke or suspend the license of a driver who repeatedly is convicted of speeding and has been warned that another conviction will bring revocation? A panel of three federal judges in Chicago ruled that a hearing is required. Yesterday, an unanimous Supreme Court reversed. UNMARRIED MOTHERS

The Martin Sweets Co., a small manufacturer of light machinery in Louisville, Ky., says its operations reflect "the high moral standards" of Martin Sweets, its founder, president and principal shareholder.

Seeking to apply these standards, a vice president in 1972 fired Rose M. Jacobs, his executive secretary, because she was pregnant but unmarried.

Jacobs sued, charging sex discrimination. The Sixth U.S. Circuit Court of Appeals upheld the charge and an award of $7,500 in back wages, noting that men - unmarried or not - are incapable of pregnancy.

Yesterday, the Supreme Court let the ruling stand. Jacobs now runs a secretarial service.