The invention discloses a treatment method of a corrosion-resistant weldable coating layer of a printed circuit board, which comprises the following steps: carrying chemical tin plating treatment on the surface of a bare Cu foil of the printed circuit board PCB; and carrying out heat treatment on the PCB after the chemical tin plating treatment, wherein the temperature of the heat treatment is higher than or equal to 232 DEG C and is lower than or equal to 245 DEG C. Through the treatment method provided by the invention, the severe environment etching resistance capability and the weldability of PCB components are improved, in addition, the weldability can be maintained and can be protected from being influenced by operation environment in the warehouse storage and shop assembling process, the manufacture is simple and convenient, the acceptance rate of PCBA welding points is improved, the rosin joint is inhabited, and the reliability of the welding points is improved.