The present invention provides a mechanical prosthetic limb, which relates to the technical field of medical devices. The mechanical prosthetic limb includes a prosthetic limb shank, a fixed component for connecting the prosthetic limb shank with a human body, a power-driven first drive mechanism that is installed on the prosthetic limb shank, and a prosthetic limb sole that is connected to the bottom of the prosthetic limb shank; the fixed component is rotationally connected with the prosthetic limb shank through the first drive mechanism; and the prosthetic limb shank is rotationally connected with the prosthetic limb sole through the first drive mechanism. It can relieve the burdens of the disabled in the automatic advance way, thereby improving convenience.