William Beasley Harris, 70, an administrative law judge with the Federal Maritime Commission since 1974 who was active in volunteer and civic organizations, died Nov. 6 at Walter Reed Army Hospital after a stroke. He lived in Washington.

Judge Harris came to Washington in the 1950s and engaged in the private practice of law and taught at Howard University law school before becoming an administrative law judge with the Federal Power Commission in 1970. He joined the Maritime Commission four years later. He also had been a special legal consultant to the State Department and had done volunteer work with D.C. Legal Aid Society.

He served as vice chairman of the Health and Welfare Council of the District of Columbia and chaired the Special Committee on the Welfare Crisis in the District of Columbia. He also directed fund-raising efforts for the D.C. Urban League and served as 1970 campaign director for the March of Dimes here. He was a member of the board of Lindenwood College of Missouri.

Judge Harris also was a member of the D.C., American and National bar associations and the Conference of Administrative Law Judges.

Judge Harris earned undergraduate and law degrees at Temple University in his native Philadelphia. Before moving here, he had taught law courses at schools in North Carolina and Texas.

His marriage to the former Marie Christmas ended in divorce.

Survivors include his wife, Patricia Roberts Harris, an attorney who served as secretary of Housing and Urban Development and of Health and Human Services in the Carter cabinet, of Washington; a son by his first marriage, William B. Jr., of Rochester, N.Y.; a brother, Paul J. Jr., and a sister, Elizabeth H. Adams, both of Baltimore, and three grandchildren.