Abstract: Huainan area is located in the southern margin of the North China plate, obviously affected by the tectonic process. The karst area has the typical characteristics of the northern karst and its own characteristics. In this paper, the characteristics of structure were studied and their influence on karstification were discussed with the method of probability and structural analysis. Structures in this area have great influences on the karst development. The location of the karst point is controlled by the hanging wall of the large scale thrust fault on the plate edge. In the study area, the NE trending and NW trending tensional fractures distribute in valleys, which are low-lying and have better water conductivity, and often become the drainage point of the groundwater, and the karst develops on both sides of them. The direction, dip, filling material and density of the joints in the study area have their respective contribution to the plane shape, vertical shape and the control of the degree and scale of the karst development.