Abstract: The pumping performance of sputtering ion pumps depends on a complex discharge process involving microscopic mechanisms such as particle collisions and gas ionization, which directly affects its ionization efficiency, pumping speed, and stability and lifespan at low pressures. Traditional experimental methods are costly and have strict conditions, while numerical simulation is efficient and controllable. Among them, the particle simulation method has become an important means to study the discharge process due to its high accuracy and applicability to non-equilibrium states. Existing research mostly focuses on macroscopic parameters and lacks in-depth analysis of the microscopic motion of charged particles and the dynamic influence of electromagnetic fields. This paper adopts the particle-in-cell (PIC) method combined with the Monte Carlo collision (MCC) method, and through three-dimensional numerical simulation with VSim software, reveals the distribution and motion characteristics of electrons and ions under different pressures, magnetic fields, and voltages in high vacuum, clarifies the influence mechanism of these key parameters on particle transport, density distribution, and ion current, providing a theoretical basis for the subsequent precise calculation of sputtering yield and pumping speed optimization, and offering reliable technical support for pump performance improvement and structural optimization.