Abstract: CSAMT was used to study the karst geological structure in the west of Xing'an, Guilin, to acquire more information of karst geology.By setting inversion parameters of different depths, the effect of grid size on the resolution of inversion results is compared and analyzed, so as to obtain a higher resolution data inversion method.The resolution of shallow geological structure obtained by small grid is higher than tha obtained by large grid; and the characteristics of shallow karst development can be effectively detected by small grid.The results show that: the resolution of inversion of shallow karst geological structure is influenced by the size of inversion grid, and with the increase of depth, the intensity of karst development becomes weaker.There may be a geothermal field controlled by NE faults in the Xing'an area.This research can be used as a reference for the efficient extract of CSAMT data, and can be used to improve the resolution of electromagnetic inversion.