The invention discloses a shape memory alloy-driving bionic wall climbing robot leg unit. The shape memory alloy-driving bionic wall climbing robot leg unit comprises bionic legs, a foot module, a shock absorption spring, a bi-directional shape memory alloy driving device and a single-directional shape memory alloy driving device, wherein the front-back and left-right movement of the bionic legs are driven by virtue of the bi-directional shape memory alloy driving device and the single-directional shape memory alloy driving device. The invention also discloses a shape memory alloy-driving bionic wall climbing robot driven by shape memory alloy. The bionic wall climbing robot comprises the bionic wall climbing robot leg unit. The shape memory alloy driving device adopts a bionic structure,so that the wall climbing movement of the robot on a medium surface is realized; the driving device is simple in structure, light in weight and flexible in movement; and the foot module adopts an ironmagnetic ball body, no surplus leg raising and re-absorption action is needed in the movement process of the bionic leg, the leg can provide a stable supporting force and absorption adsorption force,the supporting point is stable, the center of gravity of the robot is slight in change, and the gait planning is simple.