Abstract: For the mining face of close distance coal seams under the goaf, because the overlying strata of mining area formed a new structure, traditional determination method of support working resistance could not guide the roof management in this case. In this paper, it took actual conditions of No.10 fully mechanized face under the goaf of close distance coal seams of Wangsheng Coal Industry as the background. According to numerical simulation and analysis for the relationship of No.10 coal seam caving height and the coal seam spacing, it gave the calculation method of support working resistance theoretically, and determined that the reasonable support working resistance was 4 500 kN per frame, which was close to the result of field measurement.