Abstract: The geological history of coalbed methane (CBM) emission during the formation of CBM reservoir formation was studied through the design and simulation of the numerical model under the condition of multi-coal seams．Some principles for simplifying multi-coal seams into the upside, bottom．major and middle seams were suggested．A formula for adjusting the CBM emission coefficient in the simplified seams was established according to the lithological composition an dvariety of the wall rocks．The method for setting the boundary condition．In which the neighbor coal seams could be taken as the boundary of the inner seams, was discussed． The boundary condition was studied in the case that the source rock or coal seams occur above or under the simulated coal series ．The geological and mathematical models of the CBM emission in multi-coal-seams then were set up an d used in a case study in the Qinshui Basin．