Laser light source is widely used in digital projection display system in recent years,and the laser display is representing one of the future development trend of display technology.In laser digital projection display system,diffractive optical element (DOE) can realize uniform illumination on light modulator utilizing its good beam shaping ability and small size.The advantages of adopting DOE are not only higher efficiency of light source,better uniformity of illumination but also making the display system more compact.DOE that has 16 phase level is designed by using the Fourier transform step-iterative algorithm and the function of beam shaping and uniform illumination is realized.The simulation results show that the energy efficiency of light source is better than 85% ,the uniformity of illumination is higher than 90%,and the Root-Mean-Square of difference of intensity profile compared with the ideal one is less than 7%.