By setting up geoelectric model of Ehuobulake Mine, Xinjiang, forward simulation was made to analyze influence and effect of different aquifer thickness, surface thickness and electrical resistivity with finite difference method. Simulation results showed that there was obvious reflection of high density resistivity method for ancient gullies, in the form of high resistance, but for the low resistivity layer under high resistivity layer was not obvious, with the increase of the surface thickness of high resistivity layer and the resistivity value, reflection of the ancient gully gradually weakened.