The utility model discloses a bottom end bottoming clamp for CNC machining of a stretching piece. The fixture structurally comprises a fixture main body, a bottom supporting sliding block, a sliding block and a product, the right portion of the upper end of the clamp body is in sliding connection with the bottom supporting sliding block. The right portion of the upper end of the bottoming slidingblock is connected with the sliding block in a sliding mode, and a product is arranged at the right end of the sliding block. According to the bottom end bottoming clamp for CNC machining of the stretching part, the clamp body in the clamp body is shrunk through closing of the sliding block, then the bottoming sliding block is opened, and the product placed at the upper end is fixed; the product is tightly supported through the supporting sliding block, the bottom supporting sliding block retracts and supports the non-machined part of the product, and the problems that in the prior art, aftera clamp supports the bottom end of the product, it cannot be guaranteed that the bottom end of the product is located on the same plane, and a tool for chamfering a bright edge cannot be avoided are solved.