A motor bearing heat dissipation structure includes a metal base, a heat conducting element connected to the metal base and including a wall portion and an extended portion, and a plastic bearing cup located around an outer side of the wall portion of the heat conducting element and fixed to the metal base. The plastic bearing cup internally defines a bearing receiving hole. The extended portion is horizontally extended from an upper end of the wall portion toward a center of the plastic bearing cup. A bearing is received in the bearing receiving hole and seated on the extended portion, so that heat produced by the bearing when it rotates along with a rotary shaft of a motor is transferred from the extended portion of the heat conducting element to the metal base for dissipation. A fan using such motor bearing heat dissipation structure is also disclosed.