Traditional DLP technologies can not collect and utilize the light which is reflected by the micromirrors of DMD in the "OFF" state. Aiming at this defect, one design scheme of the micro DLP projection system based on a novel light pipe was presented. This system included LEDs, light pipe, color wheel, the collimation system and projection lens. A bending light pipe was added on the base of the tapered light pipe, and a compound parabolic concentrator(CPC) was used in the input end to collect the extra light reflected by the DMD. First, the related parameters of each part were analyzed and calculated according to the nonimaging optics theory. Second, the collimation system and projection lens were optimized by ZEMAX software. Finally, the model was built and simulated in TracePro software. The simulation results show that: with the number of micromirrors in the "OFF" state growing, the improving light efficiency ability of collecting light pipe first increases then decreases. Comparing with having no collecting light pipe, the light efficiency is increased by 5.33%; light pipe improves the most light efficiency, 5.91%, when half of the micromirrors are in the "OFF" state.