Abstract: In order to study the statistic distribution features of the seam dilling cutting particles, the dilling cuttings with particle diameters of 1-3 mm from She nDao Mine and Hexing Mine were collected as the test coal samples, a scanning and imaging was conducted on the different quality coal samples.Based on the MATLA B software, a digital image processing was conducted, the size of the related coal particles was obtained and the analysis was conducted on the size statistic distributio n of the coal particles. The results showed that within the 1-3 mm particle size range, the coal particle size statistic distribution was a skewed distribution and would sub mit to the Weibull distribution after a logarithmic processing.The comparison between the expected value of different quality coal samples and variance calculation show ed that when the quantity of the coal sample was over 15 g, the statistic particle size would be stable and would stabilize around 1.75 mm.Therefore, the coal sample 0 ver 15 g selected for the gas desorption index of drilling cutting was applied to the desorption measurement and the results would be more representative.