Graphene oxide (GO) sheets were obtained via an improved Hummer's method, and the Poly(vinylidene fluoride) (PVDF)/GO membranes employing GO as nucleating agent were prepared by solution casting. The crystalline behaviors and the crystallization kinetics of PVDF/GO membranes with varying GO concentration were investigated after isothermal crystallization at different temperatures. The results showed that the addition of GO induced the beta-phase formation of PVDF. The spherulite diameter reached the peak value when the content of GO was 0.1 wt%, then reduced to the minimum value at 1 wt% GO within the tested temperature range of isothermal crystallization. It is worth mentioning that the relative fraction of beta phase F(beta) was dramatically improved to 0.85 for the PVDF/GO membrane with 0.5 wt% GO at 155 degrees C. Furthermore, an enhancement of the crystallization rate was observed as the contents of GO increased in the system.