In order to solve the problem that high fill factor and accurate surface shape of the refractive lens are difficult to realize, a new approach for homogenization of semiconductor laser planar array by using diffractive micro-lens array is proposed. Diffractive micro-lens array with phase steps based on the theory of scalar diffraction is designed. The equations of intensity distribution from the input plane to the output plane are derived. The numerical simulation and experiment of the non-imaging homogenization system of diffractive micro-lens array are carried out successfully. When the diameter of the micro-lens is 0.125 mm, relative aperture is 0.1 and phase step number is 8, in fast axis, the non-homogeneity is 12.34% and the energy efficiency is 96.6%; in slow axis, the non-homogeneity is 5.42% and the energy efficiency is 95.74%. The result of the experiment agrees well with the simulated result, proving the feasibility of the system of the diffractive micro-lens array for beam homogenization.