Abstract: Based on the actual operational conditions of the sputtering ion pump's Penning discharge unit, a corresponding simulation model was established by utilizing the PIC-MCC （Particle-In-Cell Monte Carlo Collision） method. The PIC-MCC method is a powerful numerical approach. The Article-In-Cell part enables accurate tracking of charged particles' trajectories in electromagnetic fields, while the Monte Carlo collision part effectively simulates various collision processes between particles, such as elastic and inelastic collisions. After establishing the simulation model using the PIC-MCC method, the open-source code picFoam was employed to perform simulations on a single Penning discharge unit. Through a series of simulations, a large amount of data on ion incident parameters was collected. These parameters included ion velocity, direction, and position.Integrating these simulation results with well-established theoretical frameworks in the field of vacuum physics, the number of sputtered titanium atoms was accurately calculated. Furthermore, by taking into account the geometric and physical parameters of the anode cylinder, which has a significant impact on the electric field distribution and ion movement within the discharge unit, the pumping speed of a single Penning discharge unit and the overall pumping speed of the sputtering ion pump were computed. In addition, a detailed analysis was carried out on the distribution patterns of ion incidence positions, incident energies, and incident angles under different working pressures. These analyses revealed the influence of pressure on the performance of the Penning discharge unit. The results demonstrated that the computed values of the pumping speed of a single Penning discharge unit and the overall pumping speed of the sputtering ion pump were in excellent agreement with the theoretical values. This research not only provides a more in-depth understanding of the sputtering ion pump's working mechanism but also offers practical guidelines for the design and optimization of sputtering ion pumps.