A firing mechanism for a surgical stapler, wherein, the firing mechanism comprises an actuating rod provided with a stopping groove, and the firing mechanism further comprises: a firing handle rotatable relative to a housing of the stapler, wherein a pin post is provided in the firing handle, a pin groove for accommodating the pin post is provided in the firing handle, a reset component is provided in the pin groove, and the reset component is located between a second end of the pin post and an end surface of the pin groove, so that the pin post is movable in a straight line along a direction limited by the pin groove, a first end of the pin post is capable of protruding from a first end of the firing handle and entering the stopping groove, to stop the firing handle from rotating relative to the actuating rod; a button assembly comprising a pressing rod, wherein a first end of the pressing rod is inserted in the firing handle; the pressing rod is capable of further entering the firing handle, to press the first end of the pin post to move towards a second end of the firing handle; wherein, when the firing handle is pressed in an initial state, the firing handle rotates from a second position to a first position, the pin post rotates along with the firing handle, the first end of the pin post moves under the function of the reset component until the first end of the pin post enters the stopping groove, to stop the firing handle from rotating back to the second position; characterized in that, the pin post is provided with a first cooperating portion, and the first cooperating portion has a first inclined surface, a first end of the pressing rod is provided with a second cooperating portion, and the second cooperating portion has a third inclined surface; when the pressing rod is in its initial position, the third inclined surface fits with the first inclined surface. a firing handle rotatable relative to a housing of the stapler, wherein a pin post is provided in the firing handle, a pin groove for accommodating the pin post is provided in the firing handle, a reset component is provided in the pin groove, and the reset component is located between a second end of the pin post and an end surface of the pin groove, so that the pin post is movable in a straight line along a direction limited by the pin groove, a first end of the pin post is capable of protruding from a first end of the firing handle and entering the stopping groove, to stop the firing handle from rotating relative to the actuating rod; a button assembly comprising a pressing rod, wherein a first end of the pressing rod is inserted in the firing handle; the pressing rod is capable of further entering the firing handle, to press the first end of the pin post to move towards a second end of the firing handle; wherein, when the firing handle is pressed in an initial state, the firing handle rotates from a second position to a first position, the pin post rotates along with the firing handle, the first end of the pin post moves under the function of the reset component until the first end of the pin post enters the stopping groove, to stop the firing handle from rotating back to the second position; characterized in that, the pin post is provided with a first cooperating portion, and the first cooperating portion has a first inclined surface, a first end of the pressing rod is provided with a second cooperating portion, and the second cooperating portion has a third inclined surface; when the pressing rod is in its initial position, the third inclined surface fits with the first inclined surface.