The invention relates to a clamping mechanism, and particularly relates to a cam-type clamping mechanism of a slide block. The cam-type clamping mechanism of the slide block comprises a clamp body and a horizontal slide block connected with the clamp body in a sliding mode, wherein a convex platform used for abutting against the workpiece surface is arranged on the clamp body. One end portion of the horizontal slide block abuts against a cam which is in hinge joint with the clamp body, a handle is further arranged on the cam, and a reset spring is arranged between the horizontal slide block and the clamp body. The cam-type clamping mechanism of the slide block is simple in structure and low in cost.