Inertial navigation has the advantages of strong autonomy, good concealment, all-weather and all-time work, so it becomes an indispensable core navigation mode in strategic and tactical weapons, which in turn puts forward high precision requirements for inertial devices. The optical-trap-force-based atomic accelerometer adopts the closed-loop system and the influence of the friction damping of elastic support elements on the measurement results is small because there is no mechanical connection in the structure, and thus it possesses the advantages of strong anti-interference ability and high precision, which is effective to realize the miniaturization of a high precision accelerometer. According to the Rayleigh scattering model, we establish the mechanical model of the single-axis double-beam accelerometer and conduct the numerical simulation. In addition, we analyze and simulate the influence of laser wavelength, focusing degree and other optical-trap parameters on optical-trap force. Through the sensitivity analysis of the accelerometer, the parameters are optimized to obtain the measurement sensibility of 10 ^-7g·nm ^-1(g=10 m·s ^-2). The research results show that the optical-trap-force-based atomic accelerometer has a relatively high measurement precision.