When the irradiation light intensity is low, the gray value distribution of CCD camera output image represents power density distribution. Using the gray value distribution and the corresponding laser power, we calculated the laser power density on the centre pixel of laser facula area. Because laser power density is proportional to laser power, we got a series of power density value on the centre pixel of laser facula from the laser power measured in experiment. The corresponding pixel output voltage value was measured throgh oscillograph. And then we got the photoelectric response curve of CCD to 1064 nm laser. From the gray value and laser power density value, the approximate threshold value of laser intensity inducing CCD camera system saturation was 0.11 mW/cm2. And from the photoelectric response curve of CCD, the value causing CCD chip saturation was 0.20 mW/cm2.