High-precision inertial sensors have broad application prospects in fields such as aerospace, navigation, and precision measurement. However, the accurate evaluation of noise in these sensors is imperative for optimal performance, with residual gas noise being a significant source of noise in inertial sensors. The current methods for calculating the level of residual gas noise lack numerical simulations based on the actual structure of inertial sensors, which hinders the ability to meet the demands of high-precision noise analysis. This paper proposes a novel residual gas noise simulation method based on ray tracing technology. Firstly, the method simulates the trajectories of residual gas inside the electrode cage of the inertial sensor under orbital conditions using a real inertial sensor model to obtain the statistical characteristics of the residual gas acceleration noise. Secondly, the influence of different pressures and temperatures on the residual gas noise is investigated. Finally, the dependence of the residual gas noise on the gap size of the non-sensitive axis is analyzed. The simulation results demonstrate the efficacy of Ray Tracing technology in simulating and tracking the interaction between the residual gas and the sensitive structures, achieving a high-precision simulation of residual gas acceleration noise at the level of 10^-15. Temperature and pressure have been shown to significantly affect the level of residual gas acceleration noise, and reducing the gap between the electrode cage and the test mass will increase the power spectrum of the residual gas noise in the inertial sensor.