The Bulldogs expanded a 10-point halftime lead to 19 during the opening 7 minutes of the second period and moved into a tie with Virginia Commonwealth and St. Louis atop the Atlantic 10 Conference standings.
Charlotte missed a chance to make it a four-way for the lead when it fell to Temple on Wednesday.
Chase Stigall, Andrew Smith and Khyle Marshall all came off the bench to score a dozen points each and the Bulldogs limited St. Bonaventure to 19 rebounds for the entire game.
Butler reached 19-4 for the campaign and is 6-2 in conference action.
Demitrius Conger led the Bonnies (10-11, 3-5) with 20 points.