Sichuan basin contains a huge amount of natural gas resources. After more than ten years development of geological theory, shale gas exploration has made a great breakthrough. In the south and southeast of the basin, several large shale gas fields have been discovered. The main gas producing horizon is the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation. However, there are six sets of organic- matter- rich shales in Sichuan basin, and other horizons have not made great breakthroughs. The basin margin area with suitable basic geological conditions may be a favorable block for looking for economic shale gas reservoirs. Based on the analysis of previous research data, the Xujiahe Formation in the Leshan area of southwest Sichuan basin is selected as the exploration target of the new horizon in the new area. According to the regional geological conditions, the theoretical electrical model is constructed, and the numerical simulation test is carried out to determine the theoretical feasibility of the audio magnetotelluric. In addition, an audio magnetotelluric profile is deployed in the key research area. The deep electrical structure of the study area is obtained by data processing and analysis. Combined with the geological data, the geological interpretation model is provided. Combined with drilling data, it is considered that the study area has stable geological structure, continuous distribution of organic- matter- rich shales and good shale gas content. It is suggested that the upper Triassic Xujiahe Formation in the Leshan area of southwest Sichuan may have a good resource prospect as a new shale gas exploration area.