The invention provides a fin and a heat exchanger. The fin is used for being connected with heat exchange tubes and comprises a plurality of windward plates and a plurality of leeward plates; the ends, cooperating with the heat exchange tubes, of the windward plates and the leeward plates are each provided with a heat exchange tube groove; the plurality of windward plates and the plurality of leeward plates are arranged along the two sides of the heat exchange tubes in a spaced mode, and the distance between every two adjacent windward plates is larger than that between every two adjacent leeward plates; the distance among the leeward plates is small, and therefore the heat exchange efficiency of the fin is high; and the distance among the windward plates is large, therefore, the frostingspeed is decreased, the windward side is not prone to being blocked, and the fin using reliability is improved.