The Rev. Alfred R. Winham, 70, pastor emeritus of Rockville United Church and former director of the United Church Center for Community Ministries, died of cardiac arrest Wednesday at his home in Greenbelt.

Mr. Winham became director of the center in 1972. At the same time, he became Rockville United Church's community pastor -- a separate post from that of pastor to the congregation -- and held both positions until his retirement in 1978, when he was named pastor emeritus.

As a community minister, he worked on civil rights activities, youth affairs and problems of the elderly. He was a member of the Human Rights Commission of Rockville and was chairman of the Citizens Advisory Committee on Minority Relations of the Montgomery County Board of Education.

Among other things, he helped gain support for two housing projects for the elderly, the Town Center Apartments and the development of Twinbrook Housing for Seniors Inc.

With his wife, Margery, Mr. Winham was cochairman of the Social Action Committee of the Potomac Association of the United Church of Christ, which is concerned with such issues as race relations, hunger and refugees.

Mr. Winham was born in Brooklyn, N.Y. He graduated from Rutgers University and earned a bachelor of divinity degree from the New Brunswick (N.J.) Thelogical Seminary. He later studied at the Jewish Theological Seminary in New York and at Harvard Divinity School.

From 1936 to 1964, Mr. Winham served churches in New York and Massachusetts. From 1964 to 1967, he was a staff member of the Commissions on the Delta Ministry in Mississippi of the National Council of Churches. From 1967 until he moved to Rockville in 1972, Mr. Winham was a "missionary to Massachusetts" from Mississippi, was a New England organizer for Peace Action, an American Friends Service Committee group, and lectured at Trinity College in Hartford, Conn., and at Mount Holyoke College in South Hadley, Mass.

In addition to his wife, of Greenbelt, Mr. Winham is survived by two sons, Gilbert R., of Bedford, Nova Scotia, and Bruce S., of West Castleton, Vt.; a sister, Margaret Weinhagen of Pompton Plains, N.J., and five grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to Rockville United Church, 355 Linthicum St., Rockville, 20851, for the Delta Resources Committee in Greenville, Miss.