Abstract: West Guizhou has complicated geological conditions. In order to ascertain the strata distribution and structure conditions, based on the regional gravity data of the study area, the authors deduced the fluctuation of density interface and the distribution of regional faults. And then they used the deduction results of the regional gravity data to inverse magnetotelluric electrical demarcation line and faults. With magnetotelluric electrical demarcation line and faults as reference, they made forward modeling of high-precision gravity measured curve for comprehensive geophysical inference. The research can obtain more detailed and exact information of the strata and structures in the study area, and provide the data and basis for further exploration of shale gas.