The distribution of light field on silicon substrate of charge coupled device (CCD) is analyzed via mathematical modeling and experimental research. The atomic force microscope and scanning electron microscope are used to get the critical optical parameters, i.e. the micro lens surface function and the thickness of silicon dioxide thickening layer. The energy distribution of vertical incident planar light on the silicon substrate is simulated and it is compared with the experimental images of femtosecond laser illumination induced damages to CCD and they are consistent with each other. The research results shown that the coaction of micro lens and silicon dioxide thickening layer makes the laser energy almost illuminate at the sensing zone and the laser energy shows a dumbbell-shaped distribution.