A self-distribution fin tube type heat exchanger for air conditioner is comprised by upper collection tube and lower collection tube, and connection tube and connecting tube which are parallel arranged between the upper and lower collection tubes, wherein the said connection tube and connecting tube use snake tube having fins, and quantity of the connection tubes are no less than two, two of which are arranged at two ends of the lower collection tube, and each connection tube is directly connected to the upper collection tube and the lower collection tube; and the upper end of the connecting tube is directly connected to the upper collection tube, and the lower end thereof is connected to the lower collection tube and extends into liquid of the lower collection tube. The invention adopts self-distribution structure, and can realize self-distribution of vapor/liquid phases of refrigerant so as to resolve the problem that the refrigerant of vapor/liquid phases flows nonuniformly in all channels when the heat exchanger serves as evaporator; the fins are inclined arranged along windward side in order to discharge condensed water or defrosted water in time. The invention has simple structure and has good distribution characteristic, and can be applied in heat pump air conditioner or other place needing air-cooled heat exchanger.