Abstract: Based on investigations of geological characteristics of ground surface and deep parts and three-dimensional geological modeling, this study preliminarily ascertains the lithology of rock masses and the spatial distribution characteristics of faults in the Suanjingzi area, obtaining and the following understanding. In terms of lithology, the Suanjingzi area mainly consists of granodiorites with an exposed area of about 176 km² and a depth of more than 2 km. The granites occur in the form of batholith and are generally distributed in the NE-SW trending, which is consistent with the direction of the main tectonic line in the study area. Meanwhile, they feature single lithology, high integrity of deep rock masses, and slight rock alteration. There are nine faults in the study area in total. They have roughly developed in rock masses and have steep dip angles. A rock mass with an area of greater than 31 km² can be selected from the granites, which has single lithology, large enough volume, and high integrity and maybe used as a candidate site of the disposal repository of high-level radioactive wastes in the future. Overall, the Suanjingzi area has suitable geological conditions as a pre-selected site for the geological disposal of high-level radioactive wastes.