Abstract: Under the condition of combined mining in close-distance coal seams in Shigejie coal mine，to avoid the influence of roof periodic weighting on the lower coal seam during the mining process of upper seam，or the interaction of synchronized weightings between the upper and lower seams，we gives the selective method of determining the reasonable malposition in combined mining in this paper，by using the theories of semi-infinite elastic and underground pressure，and the field measurement data．The results show that：1) firstly，the malposition distance can be determined initially according to the mine geology and physical mechanical properties；2) then，the malposition should be modified after the theoretical analysis or field measurement of stress distribution zone between layers；3) finally，the reasonable malposition is determined ultimately by the examination of the field practice．According to the analysis results，selecting the sum of initial malposition and horizontal range value of the main stress effect zone between layers as the reasonable malposition distance in close-distance coal seams，can make the lower seam avoid bearing the continuous high stress from the upper seam．

Key words: combined mining, close-distance coal seams, malposition distance, semi-infinite body