Abstract: Based on mining height and the roof strata structure of close distance coal seam under goaf, the roof is divided into four types according to the power source of the support: immediate roof strata and caving zone strata, immediate roof strata and caving zone strata and fractured zone strata, immediate roof strata and basic roof strata and caving zone strata, immediate roof strata and basic roof strata and caving zone strata and fractured zone strata. According to different types of roof strata structure, support and surrounding relationship is analyzed by using corresponding mechanical models. The working face load of close distance coal seam under goaf is calculated, and then the working resistance of support is determined. The proposed quantitative calculation formula is also verified in the field of engineering practice.