The utility model relates to a V type engine cylinder block top surface mills automatic turning device belongs to the machine -building field. Include by the tight unit of cylinder body locating clip,turning device, the anchor clamps body. The tight unit of cylinder body locating clip is fixed on the roll -over table, upset 30 about turning device drive roll -over table to make the roll -over table stably keep at horizontal position. Turning device fixed mounting is on anchor clamps are personally experienced sth. Part of the body. The advantage lies in: overall structure is compact, surely move, and safe in utilization, reliable, the rigidity is good, can avoid the shaking problem in the course of working. Adopt the pneumatic tight mode of pressing from both sides, improve clamping efficiency. A clamping improves V type engine cylinder block top surface milling process efficiency and machining precision. The efficiency of production is improved, reduce fatigue power costs.