Laser diode (LD) pump coupling system is an important part of the solid-state lasers. Non-imaging system consisting of hollow lens duct coupling system is ideal for high-power semiconductor laser array. Based on geometric optics theory, the mathematic model of three-dimensional (3D) light transmission in hollow lens duct was developed, and 3D ray trace equations were clearly presented. With the help of theoretical analysis of three-dimensional ray trace, a 3D simulation software of ray transmission for lens duct as coupling systems was developed. The real transmission trace of all the pump rays can be shown automatically with the developed 3D software and the pump light distribution in output of lens duct also can be given. Finally. The coupling energy efficiency coming through the hollow lens duct was discussed. The results show that the coupling energy efficiency of the hollow lens duct can reach more than 96.08%.