In order to separate the spectrum, dichroic beam splitter has been widely used in various types of the optical system. Based on the infrared dichroic beam splitter of many-spectrum detect systems,the substrate and coating materials are analyzed. Ge and ZnS are chosen as coating materials and Ge as substrate. The initialization configuration of traditional long-wavelength pass filter is optimized by software,and optimum configuration is coated. The spectral performance and enviroment qualities of infrared dichroic beam splitter are tested. The results show that it meets the requirement of optical system. Such infrared dichroic beam splitter has been successfully applied to many-spectrum detect systems.