Abstract: Qianlishan rock mass is an important rock mass closely related to tin and tungsten mineralization in Nanling region. Studying its spatial characteristics and ore-controlling role is of great significance for deep geological mapping and deep prospecting and prediction. Using medium-scale gravity data the authors determined the hidden boundary of Qianlishan rock mass. Two-dimensional and three-dimensional simulation inversion revealed the connection relationship between Qianlishan rock mass and Wangxianling rock mass, the spatial morphological characteristics and the contact relationship with surrounding rock masses. It is inferred that the Qianlishan rock mass and the Wangxianling rock mass are connected in depth, and were produced in a large basement and controlled by deep and large faults, with the three-dimensional shape of the two rock masses being balloon expansive contour as a whole. On the basis of geological data, the relationship between Qianlishan rock mass and mineralization was discussed. It is concluded that deep bedrock and structure provided ore-forming material source, heat source and ascending channel for the deposit.