The existing Digital Light Projection (DLP) systems, in which the components such as color wheel and relay lens are used, resulting in a complex projection system. Aiming at this defection, a new DLP projection system was designed, where the three-color LED were used as the illumination light source and refractive index lens were used to produce the parallel light. Compared with the conventional projection system, components such as the color wheel, the relay lens, the mirror could be saved. Besides, the structure of the optical system was simplified. The simulation results and ray tracing by the Tracepro software show that the light spot uniformity reaches 96.9%. The results indicate that optical path of the projection system is simplified, and uniformity of the spot is also improved. The design only need to select the appropriate projection lens, that it can eliminate the influence of extended LED on the projection spot.