The invention discloses a bed for the rehabilitation exercise of the four limbs. The bed comprises a bed body, a bed board, first driving devices, brackets, an arm exercise assemblies and a control device, wherein the bed board is supported on the bed body and comprises a first bed plate, thigh bed plates and shank bed plates, which are sequentially arranged on the bed body, one end of each thigh bed plate is rotatably connected to the corresponding shank bed plate, and the other end of each thigh bed plate is rotatably connected to the bed body or the first bed plate; the first driving devices are mounted between the thigh bed plates and the bed body, so as to drive the thigh bed plates to rotate; the brackets are mounted on the bed body; the arm exercise assemblies are mounted on the brackets and are located above the bed board; the control device is connected to the first driving devices and the arm exercise assemblies and can control the first driving devices to drive the thigh bed plates to reciprocate in a certain angle range. The leg bed plates are of split arrangement, and the bed plates of left and right legs are driven to move alternately by motors, so that leg rehabilitation exercise can be realized; meanwhile, through the arm exercise assemblies mounted on the brackets, arm rehabilitation exercise can also be realized.