Abstract: Coalfield logging curve carries a great amount of geological information, and certain correlation exits among logging parameters, mechamical properties, the characteristics of gas storage and watery property of seam coal.Through the process of digitalization and standardization of logging curves, and based on negative correlation between coal-bed gas content and the parameters of natural radioactivity, and postive correlation between apparent resistivity and parameters of artificial resistivity, we have confirmed the combined parameters based on natural radioactivity, apparent resistivity, artificial resistivity, then built the relation between the gas content and the composite parameters, what's more we calculated and evaluated the coal-bed gas content of a seam in the study area with the defined parameters. The final result showed that the predicted distribution of coal-bed gas content better accorded with actual discovered distribution of coal-bed gas content.