With the help of Technology Computer-Aided Design (TCAD) 3-D simulation, the dependence of process parameters on single event transient (SET) in 25 nm raised source-drain FinFET (Fin Field Effect transistor) was studied. It is found that the fluctuation of some process parameters exert remarkable impact on the charge collection, thus affecting the SET pulse width propagated in circuits. For the best corner process parameters, the amount of charge collected can be reduced by 38%, whereas the charges will increase 79% for the worst corner process, which foumulates a new idea for the SET mitigation and radiation-harden design in FinFET.