The invention discloses a water turbine rotor buttress placing device, belongs to the technical field of water turbines, and solves the problem of potential safety hazards in the process of manual placement and supporting under lifting rotors in the placing process of rotor buttresses on traditional water turbine sets. The water turbine rotor buttress placing device comprises a car, a hydraulic cylinder, an adjusting device, a platform, a counterweight block, an adjusting rod, a rotating shaft, a lifting support column, two torsion fixtures and four support rods; the two ends of each support rod are hinged to the platform and the car; the centers of two support rods are hinged to form one support rod set; the centers of the other two support rods are hinged to form the other support rod set; the two support rod sets are arranged side by side; one support rod set is driven through the hydraulic cylinder to shift the platform up and down; the counterweight block is arranged on the platform through the adjusting device; the two torsion fixtures are fixed on the adjusting device side by side; the adjusting rod is rotationally arranged on the platform; and a hand wheel is arranged at one end of the adjusting rod. The water turbine rotor buttress placing device is suitable for lifting rotor buttresses of rotors.