The invention provides a punching die with an auxiliary punching mechanism and belongs to the field of dies. The punching die comprises an upper die base and a lower die base, wherein the upper die base and the lower die base are connected through a guide pillar, an upper male die body is connected to the bottom of the upper die base, and a round tube accommodating part is arranged on the lower die base in the longitudinal direction; the auxiliary punching mechanism is arranged outside the upper male die body and comprises a positioning block, the bottom surface of the positioning block is of a tensile structure, the contour line of the bottom surface of the interior of the longitudinal section of the positioning block is an arc, a vertical through hole is formed in the positioning block, and the upper male die body penetrates through the through hole; the positioning block is connected with the upper die base through an elastic mechanism, and the positioning block can move in the vertical direction through the elastic mechanism. By the adoption of the punching die, a round tube is more stable during punching, the upper male die body operates more smoothly, failures, such as bending, of the upper male die body are avoided, and the operation stability of the punching die is improved.