Abstract: During the study of brain mechanism of response inhibition using event-related potentials (ERP) under Go/NoGo experiment paradigm, traditional research results have shown that ERP following Go/NoGo tasks show two major differences between Go and NoGo trials at the prefrontal area. One is a negative deflection of N2 component in NoGo trials compared to Go trials, and the other is a positive deflection of P3 component in NoGo trials compared to Go trials. They are also named NoGo-N2 effect and P3 effect. The overlap of movement-related component deriving behavior response on Go trials may make true NoGo-N2 effect and P3 effect to be masked. In order to recover true NoGo-N2 effect and P3 effect, stimulus and response components decomposition method is applied to eliminate the influence of motor-related component in Go trials. Results show that NoGo-P3 effect is resulted from overlap of motor-related component and it may not relate to response inhibition processes, while NoGo-N2 effect is related to response inhibition processes.