Abstract: The very fast transient over-voltage (VFTO) in gas insulated substation (GIS) seriously affect the safe operation of the related equipment and the designing of insulating strength. So in the simulation calculation, accurate VFTO waveform under the reasonable arc model is particularly important. In this paper, virtual inductance arc model is put forward, combining with some 1 000kV GIS substation and comparing with other arc model, and detailed VFTO research of internal key equipment of GIS is made, and the influence of simulation step on VFTO is made. Result shows that virtual inductance arc model is continued of arc resistance model considering arc inductance characteristic, and it takes into account the inductance characteristics of arc compared with time-varying resistance model and the fixed value resistance model of the arc. Dynamic inductance is difficult to set up and affect the system stability in arc resistance model considering arc inductance characteristic, but virtual inductance arc model can solve the problem, so virtual inductance arc model is suitable for use when considering inductance characteristic of arc in the study of VFTO.