The invention discloses a way to design pressing tube of SCS combined hydraulic power station. Between the steel inside and the round wall fill concrete tube, between the concrete tube and the round wall fill the outside steel tube. The outside steel tube is anti-seepage , the middle concrete tube resists external pressure, and the inside steel tube only resists water pressure inside when operating. It decrease by large the content of steel and concrete and the cost, and it is convenient to transfer the water pressure from inside to outside. The way of design brings the good capability of steel and concrete into play, and apt to the work environment very well. Otherwise, in operation there is no need to add other ways, so it increases the speed of the operation by large.