The invention discloses an automatic centering and clamping device. The automatic centering and clamping device comprises a bottom plate A, a left clamping block, a dual-head screw A, a brake block A,a right clamping block, a left guide plate and a right guide plate; the left guide plate and the right guide plate are each mounted on the bottom plate A through a cylindrical pin A and a bolt B, theleft guide plate and the right guide plate are mounted on the bottom plate A to form a T-shaped guide groove, the two ends of the dual-head screw A are screwed into the left clamping block and the right clamping block to form an assembly, the assembly is arranged in the T-shaped guide groove formed by the left guide plate, the right guide plate and the bottom plate A, the brake block A is arranged in the middle of the dual-head screw A in a sleeved manner, and is arranged on the bottom plate A through a cylindrical pin B and a bolt A, the brake block A is located between the left clamping block and the right clamping block, and the brake block is of a covering type buckle saddle structure. An optimized manufacturing, assembling, detaching and adjusting scheme can be provided for the automatic centering and clamping device, the tool manufacturing and repair time can be shortened, cost is reduced, and the developing work efficiency is improved.