Abstract: MODTRAN is a popular calculation model for atmosphere infrared radiation transmission. The graphic interface for MODTRAN based on the code compiled with FORTRAN is designed for project applications. Since calculation efficiency of FORTRAN language is high, but its graphic function is weak, while the calculation efficiency of Visual Basic (VB) is low, but its graphic function is powerful, their advantages are utilized adequately, and the concept of reusing the resources of FORTRAN calculation program is realized. The method is to change the FORTRAN program into the dynamic link library (DLL) functions, exchange data between VB program and FORTRAN program by transferring function parameters, then shows the calculation results of FORTRAN DLL functions on VB form and draw the graphs. Thus the graph interface of MODTRAN calculation program is added and the results of calculation are visualized. Therefore, the Chinese graphic interface for MODTRAN was designed for the users in China.