Abstract: On the basis of summarizing development characteristics of coal bearing strata of Sijiazhuang mine in Yangquan mining area, Six layers of coal seam were selected as coalbed methane development layer to analyze composition. Based on that, logging parameters corresponding to each sampling coal seam were extracted, the linear relationship between natural gamma and ash, fixed carbon and ash, volatile matter and apparent resistivity were established. According to the volume of coal seam, it could be divided into four parts: fixed carbon, volatile matter, ash and logging fluid (pore was full of logging fluid). As a contribution to the logging response, a logging density model was established to calculate effective porosity of coal seams. The results showed that the difference between the porosity of logging calculation and the measured results were not more than 10%. The research results could be used to guide the composition analysis and physical property analysis of coal industry.