A method of making a golf club head includes the steps of: preparing a head body formed with at least one cavity, and at least one flange protruding from the head body and proximate to the cavity; mounting a counterweight unit in the cavity; bending the flange toward the cavity and pressing the flange against the counterweight unit; joining the counterweight unit to the head body using a solder; and polishing the head body and the counterweight unit to remove excess of the flange and the solder.