The Utah Supreme Court, in an unexpected move, today stayed the scheduled execution on Thursday of two convicted torture-murderers, setting the stage for possibly months of appeal.

Attorneys for Dale Pierre, 25, and William Andrews, 24, gained the 4-to-1 decision late this afternoon, canceling state prison preparations for an 11-man double firing squad at sunrise Thursday.

Lawyers Gilbert Athay, John Caine and Tim Ford had petitioned the state courts to consider new arguments, including one that Utah has not applied its new death penalty law equally to blacks and whites. Pierre and Andrews, former airmen stationed at Hill Air Force Base in northern Utah, are black.

Gary Gilmore, executed here in January 1977, was sentenced under the same law. He was white.

Pierre, a Trinidad native and former resident of Brooklyn, and Andrews, of Jonesboro, La., had been sentenced to die for torturing and slaying three people in a 1974 robbery of a radio shop in Ogden, a small railroad and university town near the base. Two other persons tortured and shot in the head survived.

Testimony at the 1974 trial, held in predominantly white, Mormon Ogden, showed that the robbers forced the five to the shop's basement, made them drink a caustic drain cleaner, lined them up against a wall and shot them in the head with a.25-cal. pistol. one of the five, a teen-age girl who worked at the shop, also was raped.

The attorneys, expecting that the state Supreme Court would not issue a stay of execution, had prepared to launch an appeal in U.S. District Court later today. The appeals will remain under file there should they be needed later.

In staying the execution pending a full review, the high court set no deadline for written appeals from both parties, leaving the door open for months of appeal.

Utah revised its death penalty law after a 1973 U.S. Supreme Court decision that struck down all existing laws on the grounds that the death penalty was not being fairly applied. Utah's law is similar to statutes in Texas and Florida that have been reviewed and upheld by the U.S. Supreme Court.

Seven men in Utah have been sentenced to die since the new statute was adopted. The Jan. 17, 1977, execution of Gilmore is the only one to occur in the United States in more than a decade. Because Gilmore did not appeal his sentence, the U.S. Supreme Court has yet to review Utah's statute.

Pierre and Andrews were the first to request a review of its constitutionality.