Abstract: The Guorbun Area in Erlian Basin has excellent conditions for uranium mineralization, with the development of fluvial sedimentary system, but the tectonic unit and the target layer of the Saihan Formation sand body are not well characterized, which has become a bottleneck restricting the breakthrough of uranium exploration in the study area. Through the controlled-source audio geomagnetic survey （CSAMT） and electromagnetic inversion using SCS2D software, the spatial distribution characteristics of the sand body of the Lower Cretaceous Saihan Formation, which is the target layer of uranium mineralization, have been deduced, and the sand body is mainly located in the Yihewusu and Saihantala Depressions, with a depth of 135-560 m and a thickness of 80-440 m. The tectonic unit in the area has been newly divided, and the boundaries of tectonic units have been controlled by the fracture. The boundaries of the tectonic units are controlled. The field geological survey and subsequent drill holes have proved the accuracy of the interpreted results, which provide reference for the exploration of sandstone-type uranium mines in the Erlian Basin.