The actual lightning impulse voltage suffered in substations is far from the standard lightning impulse voltage used in high － voltage equipment test． In order to discuss the difference between non － standard lightning impulse voltage and standard lightning impulse voltage ( 1． 2 /50 μs) actually tolerated by substation equipment，a circuit which can generate non － standard lightning voltage waveform is designed，the circuit component parameters are adjusted，and the influence of different component parameters on non － standard lightning impulse voltage waveform is studied． Most of non － standard lightning impulse voltage waveform are oscillating impulse voltage waveform，the circuit simulation is carried out with Matlab Simulink，and the circuit which can generate non － standard oscillating impulse voltage waveform is designed according to the simulation． The results show that the voltage waveform generated by the simulation circuit is basically consistent with the impulse voltage waveform measured by the actual circuit． This research lays a foundation for further exploring the dielectric breakdown characteristics of non － standard lightning impulse voltage．