Abstract: With a study conducted on the roof control, support sealing, powered support base jammed prevention and other technology for the coal mining face in a seam with soft roof, coal and floor, an analysis was conducted on the design keys of the hydraulic powered caving support about roof control, seal, and specific pressur e of floor applied in the seam with the soft roof, coal and floor, the optimization was made on the main technical parameters and the structure shape of the hydraulic po wered support and the optimized locations of the leg support points were determined.Meanwhile according to the design of the hydraulic powered caving support applie d in the soft roof, coal and floor, an optimized analysis on the support working resistance and the top coal caving height was provided.