A waist imitating device of robotic rat based on multiple-connecting-rod transmission comprises a pitch parallel connecting rod group (8) and a yaw parallel connecting rod group (2). The pitch parallel connecting rod group (8) and the yaw parallel connecting rod group (2) are respectively connected with a front joint and a back joint of a waist of a robotic rat. Under the drive of a first motor (4), crank connecting rods drive the yaw parallel connecting rod group (2) such that left-right yaw motion of the waist of the robotic rat relative to wheels and forelimbs can be achieved. Under the drive of a second motor (14), crank connecting rods drive the pitch parallel connecting rod group (8) such that upper-down pitch motion of the waist of the robotic rat relative to the wheels and the forelimbs can be achieved.