President Hosni Mubarak, in a move intended to win favor with Egypt's Christian minority, today ended three years of banishment for Pope Shenouda III, allowing him to resume his position as patriarch of the Christian Coptic Church.

A one-sentence statement issued by the official Egyptian news agency gave no indication that Mubarak had attached any conditions to the release.

Shenouda, spiritual leader of Egypt's 6 million Copts, was removed from office and banished to a desert monastery in early September 1981 by the late president Anwar Sadat, who charged him with inciting religious strife between the Copts and Moslems and of seeking to play a political role in the country.

Mubarak's decree was clearly aimed at appeasing the Christian minority here, following a court decision Sept. 30 to hand down relatively lenient sentences to 281 Islamic extremists on trial for their role in an armed uprising in the Upper Egypt city of Assyut in October 1981 in which 87 persons, including 66 policemen, were killed.

Shenouda's release effectively marks the end of the political and religious legacy passed on to Mubarak after Sadat's assassination. The late president's policies had angered both Christian and Moslem fundamentalists here, and Mubarak has sought to heal these wounds through a policy of leniency toward past political crimes combined with firmness toward any renewed political activities by either Christian or Moslem extremists.

Sadat had issued a decree on Sept. 5, 1981, annulling 1971 appointment of Shenouda as pope. He accused Shenouda of trying to become a "political leader" and of seeking to "achieve certain personal objectives" that Sadat never spelled out.

The Coptic church hierarchy never accepted this "disestablishment" of the pope by Sadat, arguing that he had been duly elected according to church regulations and could not be dismissed by a state decision.

The pope nonetheless "retired" under armed escort to a monastery at Wadi Latrun, 60 miles northwest of Cairo, where he has lived in political and religious banishment.

He is scheduled to mark his grand public reentry as head of the Coptic church by leading the Coptic Christmas Eve mass on Sunday at the main cathedral in Cairo. The Coptic church, with an estimated 22 million followers around the world, mostly in Egypt and Ethiopia, has its own calendar and celebrates Christmas Jan. 7.

The church dates back to the first century A.D., when it was founded by St. Mark. Pope Shenouda III is regarded as the 117th successor of St. Mark and his official title is Pope of Alexandria and Patriarch of the Sea of St. Mark.

The Copts comprise 10 to 12 percent of Egypt's population and are the largest Christian community in any Arab country today. They are extremely influential in business circles but hold few high posts in the government and long have felt discriminated against politically and threatened religiously by the rise of Moslem fundamentalism here.

These fears led to the birth of a Coptic fundamentalism. Sadat, believing that Shenouda was behind this movement, distrusted him and finally decided to depose him as pope in 1981, a time when Sadat was rounding up 1,600 other political opponents and religious extremists.

Ten days ago, the pope gave an interview to one of the semiofficial Cairo dailies in which he lavishly praised Mubarak's policies, insisted he had never interfered in politics "in any way" and pledged to work to create "an atmosphere of love and cooperation" between Christians and Moslems.

But Shenouda firmly rejected a government attempt to limit his authority and papal powers as a condition for his reinstatement, and apparently has been freed with no conditions attached.