The invention provides a bionic
robot and a leg structure thereof, the leg structure comprises a
thigh leg, a shank leg, a foot, a
knee joint and an
ankle joint, and the leg structure further comprises a
knee joint driving mechanism and an
ankle forward and backward lifting driving mechanism; a first accommodating cavity is formed in the
thigh shaft and is used for accommodating the
knee joint driving mechanism; a second accommodating cavity is formed in the
thigh leg and is used for accommodating an
ankle forward and backward lifting driving mechanism; the knee joint driving mechanism drives the knee joint through the first transmission mechanism so as to drive the shank shaft to rotate; the ankle forward and backward lifting driving mechanism drives the ankle joint through the second transmission mechanism so as to drive the foot to rotate. The thigh leg is provided with two containing cavities, driving mechanisms of the knee joint and the ankle joint can be moved upwards, the weight of a
cantilever at the
tail end of the leg of the bionic
robot is reduced, the rotational
inertia of the knee joint and the ankle joint during rotation can be effectively reduced, and therefore the requirement for
motor torque is reduced, the joint structure space is optimized, and the joint weight is reduced; and the flexibility and the movement performance of the bionic
robot are improved.