Based on the observation of the data measured, the illumination distribution of single LED is set to follow Gaussian function, and with this hypothesis, two forms of light array are analyzed on their illumination distribution. The law of Spyro is used to optimize space between LED in array. Comparison and analysis of the two kinds of array arrangement are given for getting the uniform illumination. The general design method and the calculation example of LED array to produce uniform illumination are also given in this paper. Keywords: Plane light source, Gauss function fitting, LED light source, Uniform illumination