In order to obtain a high uniformity of chlorophyll fluorescence active induced excitation source and more contrasting chlorophyll fluorescence parameters, the ratio of the minimum irradiance to the mean irradiance in the sample area was proposed as the index of excitation uniformity for the irradiance distribution of the sample area under different numbers of light sources and at different distances. Three kinds of basic LED arrays A0,A1 and A2 were simulated by spatial simulation. The results showed that the irradiance uniformity was positively correlated with the LED array height and LED spacing, and the irradiance uniformity increases with the increase of the number of LEDs. In the research area of 0.04m2, when the LED spacing is 0.04m and the array height is 0.5m, the irradiance uniformity of A2 array is the largest, which is about 0.920. The uniformity of excitation light distribution of LED arrays was verified using a handheld illuminance meter, and the experimental results were consistent with the simulation results. The fluorescence images were collected by CCD camera, and the leaf fluorescence distribution under different excitation array arrangement was analyzed, which provides an idea for future analysis of the difference of leaf regional emission fluorescence under high uniformity excitation light.