In order to scientifically evaluate the near field parameters involving the modulation and contrast ratio in space region for high power solid-state laser facility, the grey threshold of image segmentation in image processing is used to separate the noise and signal for the image of near field picked by CCD. The maximum square difference value is taken as the main criterion for noise threshold. The grey background can be obtained from the grey value of the most probability in the noise region. The oddity spot in laser near field can be judged based on whether the intensity is greater than Iavg(1+5σ) or not. The image smoothness technique of eight neighbor regions is adopted to process the oddity spots of pixel. Two evaluated methods for modulation are analyzed and compared with many experimental data. It is shown that two calculation results of modulation are identical, and present evaluated methods of high power laser near field parameters are much more normative.