Shape memory alloys (SMAs), well-known as the force source in space-use nonexplosive actuators, generate force through temperature-based phase transitions. The force amount is related to the volume and mass of the SMA. This study presents a method to improve the force-generation profile of the SMA actuator, which consists of an SMA tube, a mechanical restraint, and a heater. The high SMA mass ratio of the actuator allows it to achieve high power density; however, its force trajectories are affected by the environmental temperature variance because of its huge heat capacity. The uncertainties of the force trajectories limit the applications of the actuator. This paper proposes a method to achieve the required force trajectories under temperature variance to enlarge the application of the high power density SMA actuators. In addition, a suitable model is established for the force-trajectory control method based on the thermo-mechanical coupling response characteristics. A thermal balance model is constructed under vacuum environment. Furthermore, a hysteresis characteristic model of the phase transformation is introduced, and it reduces the heating profile limitation. The force trajectory is designed based on the model predictive control method. The designed trajectory is realized using a simple temperature-measurement feedback control method based on the proportional-integral-derivative method. To illustrate the system design, the holding– release mechanism application is selected. The effectiveness of the proposed methods is verified through specific test piece system identification and control simulations, which are performed both numerically and experimentally under temperature variance.