A stator assembly, an electrical motor having the stator assembly, a wind power generator set and a method for cooling a stator assembly are provided. The stator assembly includes a stator support and a stator core mounted on the stator support, wherein the stator support includes a support enclosure plate, a first axial air flow channel is formed between the support enclosure plate of the stator support and a radial side surface of the stator core, and the first axial air flow channel is used for receiving a first cold air flow, so that the cold air flow can flow in the axial direction. The stator assembly can introduce a cold air flow from the other side, opposite an air gap, of a stator during the operation of an electrical motor, so that two radial sides of the stator can be cooled at the same time.