Spatial buffer analysis is one of the important and basic spatial operation functions of geographic information system.
Studying 2D spatial buffer generation and analysis was more than the 3D spatial presently, thereby a novel 3D buffer
generation algorithm based on vector was presented in this paper. 3D spatial solid is represented by B-Rep model and it's
buffer is categorized into solid boundary buffer and solid interior, then construct the whole buffer by union operation on
them. The boundary features of 3D spatial solid are classified into point feature, line features and face features. Usually,
the statistical analysis is necessary after solid buffer generation. Thus, we proposed a new method which can quick judge
whether the buffer affecting the surrounding objects based on collision detection theory. Finally, taking the surface and
underground 3D space around University City region of Xianlin as the research area, a 3D buffer with complex
geological environment and man-made buildings is created based on the new presented algorithm, and spatial statistical
analysis is achieved based on the generated 3D buffer. The results show that the improved algorithm is efficient and
practicable, especially the proposed 3D buffer generation algorithm based on vector is applicable for convex body and
concave body comparing with current approaches.