The invention discloses a bending processing method of a heat exchanger. According to the method, the heat exchanger can be bent only by holding a position of a holding part of the heat exchanger and enabling the holding part to bend according to a ruled track through controlling gestures of the holding part without using a bending mould. At this moment, a contact position of a free part of the heat exchanger which is not held and a guide part is determined by a reacting force generated during the bending process, and no limitation force is generated by the free part which is not held, so that buckling generated by the heat exchanger during the bending process can be avoided. The bending processing method of the heat exchanger, disclosed by the invention, can suppress deformation and buckling of heat transfer fins.