Diffractive optical elements （DOEs） are used to directly modulate a laser beam to produce controllable interference fringe for the recording of a volume holographic grating. An optimization algorithm based on Gerchberg-Saxton （GS） algorithm was proposed to improve the output light field. The simulation results showed that the fringe uniformity produced by the optimized DOE increased from 80.15% to 88.06%， the fringe contrast increased from 28.42 to 68.95， and the error function reduced from 8.26% to 5.24%. The experimental results based on liquid crystal spatial light modulator showed that the fringe contrast and fringe uniformity obtained by this algorithm were improved compared with GS algorithm.The proposed optimization design method could help increase the practicality of using an DOE to record volume holographic grating.