The invention relates to the production field of a circuit board, specifically a circuit board welding method. A welding apparatus is adopted for welding; the welding apparatus comprises a rack, temperature reduction fans, a conveyor belt, a welding mechanism and a control mechanism; supporting plates are fixed on the conveyor belt; the welding mechanism comprises electric soldering iron, an air cylinder and a welding fan; an exhaust port is formed in the air cylinder; a reset spring is arranged in the air cylinder; the control mechanism comprises a stop mechanism and a cooling mechanism; eachof the stop mechanism and the cooling mechanism comprises a cooling fan and an airbag separately; a material inlet is formed in the airbag; on-off switches are fixed on the rack; a compression springis arranged on the rack; and the welding steps comprise (1) preparation, (2) fixation, (3) welding, and (4) workpiece taking. By virtue of the scheme disclosed in the invention, a flexible circuit board can be welded while the supporting plates can be cooled.