Fault modeling is the main process in 3D geological structure modeling. In the process of fault modeling, the geometric surfaces should be cut according to the spatial contact or cutting relationship between faults. At present, the most approaches use the TIN intersection for surface cutting, but this algorithm is often unstable when handling the cutting relationship of complex fault surfaces. This paper proposes the method and process of complex fault network processing and automatic modeling based on regular grid, and discusses the core steps such as formal theory expression of fault network model, modeling process, spatial relationship construction of fault network and cutting processing algorithm in detail. Using test data and three- dimensional seismic structure interpretation data of coal mine, this approach can effectively handle multiple fault networks with complex fault relationships, and has good algorithm stability; By comparing with the SKUA—GOCAD fault modeling method, it can reduce the interaction process and improve the automation of fault modeling.