Abstract: The technology of the blue light semiconductor laser excitation phosphor to produce the white light source is developing rapidly. However, due to the large difference of the light field distribution in the fast axis and slow axis direction of the high-power blue light semiconductor laser, the overall optical properties of the laser illumination are still poor, which is difficult to achieve the large-scale application. Aiming at this problem, a high-quality laser illumination optical system was designed based on the Monte Carlo ray tracing theory. The collimation regulation of the laser beam was carried out, the uniform light spot was shaped, and the fluorescent sheet was designed, so that the components of overall light source modules obtained the optimal integration, and the narrow beam laser illumination was finally realized. The simulation results show that the light collection rate of the laser light source reaches to 98.3%, the ununiformity of the laser spot is 1.7%, the uniformity of the white light is 98%, and the light spot is the square narrow beam white light spot with an exit collimation angle of 1.6°.