In order to improve the uniformity of the blue light semiconductor laser beam, a mathematical model of the uniform light system was established using Fourier optics theory, and theoretical analysis was conducted. The uniform light system was simulated using software, and a blue light uniform light system based on a microlens array was built. By using this system, a uniform light spot with a uniformity of 87.6% was obtained. The experimental results show that the uniformity of the homogenized spot is not only related to the focal length and aperture of the microlens array sublens, but also to the focal length of the focusing lens. The uniformity of the homogenized light spot obtained by using a Fresnel lens with a focal length of 100 mm is about 9.2% higher than that obtained by a Fresnel lens with a focal length of 80 mm. This study provides theoretical and design ideas for a blue light beam uniform system with high integration and light volume.