Gov. William Donald Schaefer has nominated Prince George's County Circuit Court Judge Albert T. Blackwell to the Maryland Court of Appeals, the state's highest court.

Schaefer nominated two other men to lower court vacancies yesterday in his first action on judicial appointments as governor. He named lawyer Elroy G. Boyer to the Kent County Circuit Court, and former state delegate William T. Finan to the district court in Cumberland.

Blackwell, 57, has served on the Prince George's Circuit Court since 1975. He would replace James F. Couch Jr., who retired from the Court of Appeals last month. If confirmed by the state Senate, Blackwell must be approved by the voters in 1988 to continue his 10-year appointment.

Blackwell has a reputation as a thoughtful and painstaking jurist. He has handled a full range of civil and criminal cases in the county.

Blackwell, director of the Upper Marlboro Redevelopment Commission, graduated from the University of Maryland and George Washington University law school. He lives in Upper Marlboro.

Boyer, 67, of Chestertown, graduated from Washington College and the University of Maryland law school and has practiced law on the Eastern Shore. He was named to a 15-year term on the bench, and must be confirmed by the Senate and approved by the voters in 1988.

Finan, 36, was a member of the House of Delegates from 1982 to 1986. He currently practices law in Cumberland, and in the late 1970s was an assistant state attorney general. He was nominated to a 10-year term, subject to Senate confirmation.