The Prince George's County Board of Education reelected Jo Ann T. Bell as chairman by acclamation last night after being told that the only other announced candidate for the post, board member Bonnie Johns, had announced that she wished her name withdrawn from consideration.

Bell, a housewife, has been on the board since 1976 and been its chairman for the past year.

Johns, the board's only black voting member, became a surprise candidate for the post last Monday when board member Norman (Chuck) Saunders declared he would nominate her for the position. Saunders, a conservative who has had differences with the liberal Johns in the past, said electing Johns would be a show of good faith in her and, by extension, to the black community in Prince George's County. Almost half of the students in the school system are black.

Johns was taken ill last Monday night and is now recovering in Prince George's General Hospital from what she says was a serious infection that aggravated a "borderline diabetic condition."

Johns, an administrator with the Community Mental Health Center in Cheverly, said that while the illness may have indicated a need to slow down, it was not her primary reason for declining the post. Johns said she felt she could continue to be most effective representing the predominantly black Seat Pleasant-Glenarden community without taking the chairmanship.

After four reelected school board members and board newcomer Catherine Burch were installed last night, the board took a "five-minute break" that lasted a half hour. Then Saunders read a telegram from Johns announcing her withdrawal.

Saunders nominated Leslie Kreimer, also regarded as liberal, for vice chairman; Kreimer was to have been Johns' running mate. With Johns absent, the result was a 4-to-4 tie between her and Bell's running mate, Doris Eugene.

After another half-hour recess, Kreimer nominated Eugene, who was elected by acclamation.