Abstract: In the process of BIM design of railway tunnel, a lot of repetitive modeling work takes up a lot of time of designers. In order to minimize the energy consumption of the designer, the CAA secondary development program was implemented in C++ language, and a large number of repetitive tasks that need to be done manually by the designer are handed over to the computer after screening and judgment. The program was applied in the BIM modeling process of Mujia passenger dedicated line. Practice shows that this method can generate BIM model more accurately, efficiently and intelligently than traditional modeling methods.