Linear equations are established from density and acoustic logging with volumetric model of rock. Each volume of the rock compositions is calculated and converted to porosity curve. Impedance and porosity data are inversed from seismic, density, velocity and porosity data of the first mining area in Xinyi of Shandong Province. The porosity distribution of the Ordovician limestone is obtained by attribute extraction providing basic information for water prevention and control work of coal mine.