A surface treating method for a golf club head made of carbon steel basically has one nitriding step and two oxidizing steps. The method further has polishing, sandblasting and rinsing steps and so on processed prior to or between the basic steps, and then has polishing and oil immersing steps and so on processed after the basic steps. The finished golf club head has uniform dark appearance and also has good corrosion resistance and abrasion resistance. Furthermore, the surface of the finished golf club head does not peel off. Moreover, the method also has advantages including low pollution and low cost.