In　the　wind　generator,　a　large　amount　of　heat　is　generated　during　the　operation,　which　usually　causes　severe　temperature　rise　and　decrease　of　efficiency.　By　coupling　fluid　dynamics　and　heat　transfer,　a　numerical　method　has　been　developed　to　calculate　the　velocity　filed　and　temperature　distribution　of　a　common　air-cooled　doubly-fed　wind　generator.　The　numerical　results　have　been　verified　by　the　experiments.　The　results　show　that　the　flow　resistance　is　higher　in　the　center　in　the　axial　direction,　thus　the　temperature　is　much　higher　than　the　ends.　In　the　height　direction,　there　locate　the　most　dangerous　points　and　the　temperature　rise　is　about　110K.　In　the　circumference　direction,　there　are　regularity　of　fluctuation　and　can　assist　in　finding　the　dangerous　points.　The　variations　of　heat　source　and　cooler　power　as　well　as　rotation　speed　all　affect　the　temperature　rise　of　the　generator.　The　regularity　and　method　of　this　study　can　be　applied　to　similar　generators　or　generators　of　other　forms,　thus　advice　can　be　given　for　the　design,　manufacture,　operation　and　maintenance　of　wind　generators.　©　ICOPE　2019　-　7th　International　Conference　on　Power　Engineering,　Proceedings.　All　rights　reserved.