By useing the count of the well-logging data and the way to proving the mathematical model, and with taking the 3# coal in Chengzhuang mine as the object of study,the the variation trend of the mechanical properties of coal-rock (modulus of elasticity, Poisson"s ratio)are researched in different gas-saturation. The result shows that the gas-saturation has a big influence on the modulus of elasticity, and the influence is considerable when there are more gases. The modulus of elasticity decreases obviously with the increase in Gas-saturation, They have good interrelations, and the regularity is strong. The regularity of the influence that the gas-saturation has on the Poisson"s ratio is more complex., The Poisson"s ratio decreases obviously with the increase in Gas-saturation. They have a poor correlation and regularity.