The Board of Bishops of the African Methodist Episcopal Zion Church, meeting here this week, ordered all agencies and units of the church as well as its schools and colleges to get rid of all investments within two years in corporations doing business with South Africa.

The bishops' divestment order is part of a growing movement of churches, white and black, to force the white dominated South African government to end apartheid.

To give added emphasis to their concern, the church's 12 bishops led clergy and lay members in an antiapartheid demonstration at the South African Embassy Thursday afternoon. Fifty-one persons, including the entire board of bishops, were arrested when they defied police orders not to congregate in front of the embassy.

All were subsequently released on their own recognizance.

In their resolution, the AME Zion bishops also called for "an end to United States government support . . . military, financial, commercial . . . of South Africa" and urged state and municipal governments to divest from South Africa-related businesses as well.

The bishops said their protests of apartheid in South Africa was "on a visceral level" as a result of "our own struggle with the race question" in this country.

The bishops called South Africa's white regime "a white, Western patina on the southernmost tip of a primarily black, Third World mass" that "continues to thrive only by the support of other countries like Israel and the United States.