Abstract: Research on the selection of reasonable mining methods for shallow-buried and extra-thick under-slope coal in an open-pit mine.First, summarize and analyze the advantages and disadvantages of the four under-slope coal mining methods; Secondly, a comparative analysis and comprehensive evaluation of adaptability of the layered fully-mechanized sublevel caving and whole layer fully-mechanized sublevel caving mining methods are carried out from the aspects of economy and safety.The results show that the underground whole layer fully-mechanized sublevel caving coal mining method can effectively solve the problems of difficult roof management that caused by multiple exposures, serious spalling and roof falling of coal wall, easy spontaneous combustion of coal seam, and the stability control of under-slope wall.At the same time, it reduces the amount of roadway excavation, avoids the loss of coal pillars in layered fully-mechanized sublevel caving mining, reduces equipment input costs and mining face moving costs.It can greatly increase the recovery rate of coal resources, reduce the production cost per ton of coal, and is more applicable to mining the under-slope coal with shallow-buried and extra-thick, fissures developed, and easy to spontaneous combustion.It provides a reference for the mining method of under-slope coal in open-pit mines with similar deposition condition.