Abstract: The westward traveling surge (WTS) of aurora is defined as an important signature of the substorm onset. It is a special motion form of aurora which appears in the wake of the precipitation of the electric particles. There have been many works about calculating of electric field, conductivity and field-line current distribution in polar region during WTS. This paper puts forward a dynamic model of WTSin two-dimension plane. With the beginning of the sbsorm and following the precipitation of the electrons into inosphere, the gradient of ion density occurs (gradient of sonductivity). At the same time low frequency drift wave is excited in background electric field and its propagation reflects the main feature of WTSmotion.