A variable-pitch vertical-axis wind turbine comprises supporting rods, a double-cantilever frame, flow baffling plates, bearings, a guy cable, a tightening screw, a blade and a double-cantilever frame. An I-shaped connecting rod is respectively connected to two L-shaped curved bars in virtue of flanges arranged at the two ends of the connecting rod to form the double-cantilever frame; the two supporting rods enable the double-cantilever frame to be arranged on a rotating spindle in a slant pulling manner; the two ends of the blade are inserted into the upper flow baffling plate and the lower flow baffling plate; in virtue of the tightening screw, the guy cable penetrating the inner chamber of the blade fixedly connect the three, namely the blade and the flow baffling plates, to be a blade installation assembly; rotating shafts with the same coaxial line are respectively fixedly arranged outside the two ends of the flow baffling plates positioned in the vertical direction of the blade installation assembly, and the free rotation of the blade installation assembly in the double-cantilever frame in virtue of the bearings is ensured; and the double-cantilever frame adopting a direct-drive mode is mounted at the lower end of the blade assembly. The variable-pitch vertical-axis wind turbine is convenient in installation and dismantling, can reduce local stress of the blade installation, is free from the limitation of the blade installation length, can reduce wind wheel swept area and wind resistance, and facilitates the expansion of the generated output of the wind turbine by adopting the modularity design.