With the help of IGES standard file which was the exchange specification of initial graphics, different CAD system could change the data of product by neutral file’s format conversing. The automatic generation of 3D-Model curve surface in the MCNP input file was realized by using VC++ language.This method has solved the problem of the complication of MCNP geometric modeling process and the 3D-Model input problem in the MCNP. The input of MCNP was transferred the application problem of CAD/CAM software. The data and figure of varies software co...