A bearing cooling structure includes a metal base seat and a plastic bearing cup. The metal base seat has a raised section and an extension section. The plastic bearing cup encloses the raised section and has an inner circumference defining a bearing hole. The extension section horizontally extends from the raised section toward a center of the plastic bearing cup. The extension section has a free end and an upper surface positioned in the bearing hole. A bearing is received in the bearing hole and disposed on the extension section. A bottom face of the bearing is in contact with the upper surface of the extension section. Accordingly, the heat of the bearing can be transferred (conducted) through the extension section to the metal base seat to be dissipated. A fan with the bearing cooling structure is also disclosed.