The invention discloses step-type fish passage facilities suitable for the steep slope of a high dam and a control method, and relates to intersection fields of aquatic engineering and hydraulic engineering, in particular to a fishway building suitable for the steep slope of the high dam and a fish passage control method. The fishway in the invention is a step-type fishway building established onthe steep slope of the dam body, which is combined by step-type relays of a plurality of rectangular pools, and also comprises a fish passage monitoring system, a computer automatic control system, anoverflow water fish luring device in the fishway and a fish luring device of inlet and outlet of the fishway. The invention can lead the migratory fish to pass the dam timely without injure of the migratory fish and has the outstanding features of low physical ability consumption, no inverse effects on gonadal development, high automatic degree, relative shorter fishway (steep slope) and saving investment and the like, thus fundamentally changing the defect that other structural types of fishway pass through the high dam.