Abstract: Because of the greenhouse effect of SF6 gas,it became a common view that less or no SF6 gas would be used in future.The partial discharge（PD） characteristics of C4F8/N2 gas mixtures and the possibility of substituting SF6 gas used in gas insulated equipment were discussed.The partial discharge inception voltages of C4F8/N2 gas mixtures were measured in different gas pressures,mixing ratios and electrodes distances,and compared with that of pure SF6 gas.The influences of these factors were also analyzed.The results show that the partial discharge inception voltages of pure C4F8 gas are about 1.3 times of that of pure SF6 gas;the C4F8 gas has a synergism with N2 gas,and the synergism factor is about 0.45;and the partial discharge characteristics of C4F8/N2 mixtures are similar to that of SF6/N2 with the same mixing ratio.Therefore,after considering the liquefaction temperature,the effects on environmental and the characteristics of partial discharge,it has a possibility that C4F8/N2 gas mixtures can be used in gas insulated equipment for substituting SF6 gas.