3D numerical model construction of real geological body is the challenge faced by numerical analysis in rock mass engineering, resulting in that the comparative study between different constructing methods of 3D numerical models of large and complex geological body has great significance. Based on 3DMine digital model, the coupling modeling methods of 3DMine-FLAC3D and 3DMine-Surfer-Rhino-ANSYS-FLAC3D are put forward; and then the concrete steps of every modeling method are described in detail. Besides, the advantages, disadvantages and applicability of every modeling method are further analyzed. Through contrasting the advantages and short boards between each modeling method and learning from each other, the defects that exist in coupling modeling method of 3DMine-FLAC3D are improved; and the constructing problem of 3D numerical model of complex geologic body is solved as well. With the background of zinc-polymetallic ore body in Guangxi Tongkeng Mine, the 3D numerical modeling method of large and complex geologic body is utilized to construct the 3D numerical model of zinc-polymetallic mine and analyze the surface subsidence law for ascending mining. Research achievements play an important guiding role in accurately constructing the 3D numerical model of large and complex geological body.