A high-power LED uniform light source with one large-size near-focus aspherical lens is designed based on the principles of geometric optics and non-imaging optics. First of all, the parameters of the aspherical lens are obtained according to the geometric optics theory. Then, the aspherical lens is optimized in ZEMAX according to the evaluation function to focal length of 76.79 mm and diameter of 200 mm. The aspherical lens is further imported into the software TracePro for ray tracing simulation. According to the simulated results, the aspherical lens is machined for the next experiment. The experimental results indicate that the uniform light source can reach the target with a divergence angle of ±8.53° at 60 cm and uniformity of 95.82%.