Icing of power lines, lightning and other natural disasters often bring about line tripping accidents and cause huge economic losses to the power system. In order to increase the ice melting efficiency of power lines and improve line icing phenomena, studied the effect of covered water conductivity to ground insulator icing flashover voltage, and simulated and analyzed insulator RCSE100C-2 by finite element software Ansoft. The results show that covered water conductivity affects ground insulator icing flashover voltage, the greater the conductivity, the lower the flashover voltage is; Under the same conductivity, dry flashover voltage is higher than wet flashover voltage.