A new method on calculate the impulse performance of single vertical grounding electrode is presented. Firstly based on the integral equation of electromagnetic field and the interpolation，state equations reflect the change of the conductive currents on the grounding electrode can be derived，then Euler method is used to get the numerical solution of the state equation，and the impulse impedance curve and the distribution of potential on the ground can be calculated. Finally，example shows that this method can analyze the impulse performance of grounding electrode accurately.