A heat exchanger and a processing method of heat exchanger. The heat exchanger includes a collecting pipe, a fin and a number of heat exchange tubes. The heat exchange tubes are fixed with the collecting pipe. At least part of the fin is fixed between two adjacent heat exchange tubes. The heat exchanger includes a coating with a first matching coating which is in direct contact with at least one of the collecting pipe, the heat exchange tubes and the fin; or, at least one functional films is further spaced between the first matching coating and at least one of the collecting pipe, the heat exchange tubes and the fin. The first matching coating includes a hydrophobic material and a filler of nanoparticle type.