Based on Synopsys 3D-TCAD device simulation, the relationship between anti-radiation performance and process parameters of FET had been studied in 65 nm bulk silicon CMOS technology. The N-well doping effect on the single event transient of P-type field-effect transistor had been analyzed. SET current components of each device ports were analyzed and discussed. The influence of N-well doping concentration on SET pulse width and substrate/source had been researched. It was found that increasing the doping concentration of N-well could effectively reduce the substrate hole current by lifting the N-well’s electric potential, which inhibited the effect of parasitic bipolar amplification and then reduced the pulse width of SET. It had important guiding significance for improving the anti-radiation performance of transistors with process adjustment.