The invention relates to an accelerated fatigue test device for solid propellant grain, which comprises a base frame, a stepper motor, a traction pair, a rear fixture, a ball screw, a front fixture, afixed sliding slot and a movable sliding slot, wherein the base frame is fixed on the foundation, and a motor base, a support base and a tailstock are sequentially installed and fixed on the base frame; the stepper motor is installed and fixed on the motor base; the fixed sliding slot is installed and fixed on the support base, the movable sliding slot is in embedded connection with the fixed sliding slot, one end of the movable sliding slot is equipped with the traction pair, and the traction pair is in embedded connection with the ball screw; and the front fixture and the rear fixture are respectively fixed on the movable sliding slot and the tailstock, and two ends of a grain test piece are respectively embedded in slots of the front fixture and the rear fixture, and a rubber pad and acover plate are sequentially placed for fixation. The accelerated fatigue test device has the characteristics of low cost, simple structure, convenient adjustment and the like, and is easy to realizeaccelerated fatigue tests for the solid propellant grain test piece under small amplitude, low frequency and various amplitude-frequency combination test conditions at the same test installation state.