The invention discloses a joint rehabilitation auxiliary therapeutic instrument for old people. The instrument comprises a seat, a knee joint moving mechanism, an elbow joint moving mechanism, a controller and a remote controller; the knee joint moving mechanism comprises a bottom plate, a rail arc plate, a hydraulic driving assembly, a sliding seat, a lifting driving assembly, a crank connectingrod assembly, pedals, a moving rod and a knee joint shield; the elbow joint moving mechanism comprises a fixed arc plate, a rotating arc plate, an elbow joint shield and a rotating driving assembly; and the controller comprises a master control circuit board, a displacement control circuit board and a speed control circuit board. According to the technical solution, the instrument adopts the sliding fit among the bottom plate, the rail arc plate and the sliding seat, realizes the reciprocating motion of the pedals through the control of the crank connecting rod mechanism, simulates the walkingposture, effectively achieves the auxiliary treatment effect of joint rehabilitation, controls the controller through the remote controller, can be conveniently adjusted by a user, and has simple operation and high intelligent degree.