Abstract: In this paper, a 3D Particle-in-Cell numerical simulation model of DC magnetron sputtering source based on an existing structure is built. By simulating plasma behavior and distribution characteristics of argon glow discharge in an existing magnetron sputtering source structure, information about target utilization efficiency and also power efficiency can be obtained. Analysis of ion trajectories, energy and incident angle distribution indicates that bombarding ion portion decreases from 80% to 67% with the discharge voltage increasing from 260V to 340V due to the spatial distribution of electric potential. Since ions can be accelerated both moving toward and away from the target, an over-high discharge voltage is not beneficial to increasing power efficiency. On the other hand, increasing discharge voltage facilitates ions to impact the target with higher mean kinetic energy, which is beneficial to increasing sputtering yield. Therefore, choosing a proper discharge voltage according to working pressure is an effective way to increase power efficiency. Since the reliability of the simulation model is verified by comparison of ion sputtering position distribution and target actual erosion profile, simulation and analyzing methods in this paper are useful for the optimization design of the magnetron sputtering source.