A vertical wind power generator comprises a tower column (1), at least one generator unit (2), at least two blades (3), an excitation control device (16), a rotation rectifying device (161), a bidirectional frequency converter (15), flanges (7-13), bearings (4-6), a cooling system, a crane (80) and a lift system. The generator unit (2) comprises a bracket (201), a generator (202) and an exciter (203). The bracket (201) comprises an outer bracket (2011) and an inner bracket (2012). The generator (202) comprises a stator (2021) and a rotor (2022). The exciter (203) comprises a stator (2031) and a rotor (2032). The vertical wind power generator can be manufactured at reduced cost, be rapidly started, improve the utilization efficiency of wind power, have a better cooling effect on the generator (202) and increase its operating life, and therefore reduce maintenance cost and time.