In order to study the characteristics of electric sounding curve corresponding to different laying depth of the membrane in detection of impervious membrane in Vertical Laying plastic Film project, several groups of indoor experiment with different laying depth of membrane paving inside the saturated soil using DC resistivity method were taken. It was found that the electrical sounding curves of the measurement of the point on the surface of the sand above the membrane along the cross-section of the membrane character as follows:the apparent resistivity corresponding to the detection range of each electrical layer changes with constant gradient which has a close relationship with the laying position of the membrane.