Two most important factors in diffractive optical element (DOE) design are error value and efficiency of light utilization of intensity distribution in the output plane.The DOE designed by classical Gerchberg-Saxton algorithm possesses high efficiency of light utilization but large relative error.Tradition intelligence optimizatio n algorithms are inferior to Gerchberg-Saxton algorithm in efficiency of light utilization in DOE design,but surpass the latter in error control.In this paper,a detailed approach based on firefly alg orithm is proposed against the deficiencies of both Gerchberg-Saxton algorithm and traditional intelligenc e optimization algorithms.The design of laser homogenizer is reported as an i llustration example in which high efficiency and beam uniformity are achieved.In the simulations,the laser ho mogenizer with efficiency of light utilization up to 92.91% and relative error down to 0.60% is achieved after 5000iterations by making use of the firefly algorithm.