In this paper, based on the SALOME platform, Open CASCADE works as the geometric modeling engine and adopts the idea of replacing a surface with an entity and Cell hierarchical multinomial tree structure to carry out the research on the Inversion of the computing model and 3D visualization method. Based on this method of this paper, the inversion visualization program module SALOME-MC is developed, and the module can realize the functions of Monte Carlo computational model geometric modeling, material modeling, and model 3D visualization. Three typical reactor models were selected to test and validate the method and procedure, the test results show that the method and program can properly handle the complex geometry and large-scale repeated structure of the Monte Carlo calculation model, and accurately realize the CAD three-dimensional inversion visualization of the Monte Carlo calculation model, which proves the correctness and reliability of the inversion ability and visualization effect of the SALOME-MC Monte Carlo calculation model, and improves the geometric modeling efficiency and display degree of the Monte Carlo calculation model.