The invention aims to provide a variable-pitch vertical-shaft wind turbine which comprises a power generator, a tower frame, wind wheels, a main shaft, blades, servo motors, main shaft encoders, an anemoscope, an anemometer and a variable-pitch control system, wherein the main shaft and the power generator are respectively mounted on the tower frame; the wind wheels are mounted on the main shaft and rotate round the main shaft; rotary motion of the wind wheels is transferred to the power generator via chain transmission; the blades are mounted on the wind wheels to autorotate and can rotate round the main shaft along with the wind wheels; the servo motors are connected with the blades; the main shaft encoders are respectively connected with the main shaft and the wind wheels and rotate along with the wind wheel to collect instantaneous positions of the wind wheels; the anemoscope and the anemometer are mounted above the main shaft encoder; the power generator supplies power to the variable-pitch control system; and pitch angles of the blades are controlled by the variable-pitch control system. The variable-pitch vertical-shaft wind turbine has the advantages that the startup wind speed of the wind turbine is reduced, the startup performance and the wind energy utilization rate are improved, the working range of the wind turbine is extended, the system flexibility is high, the application range is wide, and the economic benefits and the social benefits are remarkable.