A method of produce phase-only Fresnel Computer Generated Hologram (CGH) was researched, and an algorithm for the phase-only Fresnel CGH was presented. Firstly, numerical simulation algorithm of Fresnel diffraction was studied. Computation speed of two numerical simulation algorithms was analyzed. The iterative feedback algorithm of phase-only Fresnel CGH was obtained by combination of the iterative algorithm and Fresnel diffraction numerical simulation algorithms and the proportional feedback. Secondly, experimental research of selection of proportional feedback factor k was given and the optimal empiric value of k was obtained. Simulation results show that reconstruction noise is reduced and the quality of the reconstructed image is improved. Finally, an experimental system for hologram display based on liquid crystal on silicon was built and the algorithm was verified by the optoelectronic experiment.