Holographic AR display is an augmented reality display technology with important application prospects for its ability of real 3D display. In this project, the feasibility of AR holographic display is analyzed by the information quantity conservation of optical imaging system. And an AR display system with free-form lens as combiner is designed and carried out based on LED illumination. The light emitted by the LED is collimated by a lens, and then partially reflected by the beam splitter to illuminate the LCOS. The diffracted light modulated by hologram on LCOS is filtered by a 4f optical system and reflected into free-form lens combiner by a mirror for augment reality display. Optical experiments show that the proposed system can achieve high quality imaging at different depth without speckle noise.