Abstract: The time model and dynamic model of the actuator in the stretching process was established to investigate the working condition of screw-driving actuator for mortar projectile with reciprocating canards. The effects of the length and initial angle of the connecting rob on the stretching response time and the output torque of the motor were discussed. The calculated results indicate that when the motor rotation speed is 3 000 r/min, the stretching response time is less than 25 ms and meets the engineering requirements. When the maximum aerodynamic force is 30 N, the actuator can freely control the reciprocation of canards, and the essential motor torque is less than 0.5. The greater the length and initial angle of the connecting rob are, the smaller the value of the motor output torque is and the smoother the fluctuation becomes.