By adopting the surface tension test, contact angle measurement, plating film measurement, salt film quantity measurement and metallographic microscope test, a research has been conducted on the effects of the addition of cetyl trimethyl ammonium bromide (CTAB) , fatty alcohol polyoxyethylene ether, and the surfactant mixtures of the two on the properties of hot dip galvanizing, followed by an investigation of the effects of the surfactant on wettability and salt film capacity of the new-typed plating aid, as well as an observation of the morphology change of the salt film. The research results show that the surface tension of the plating solution has been reduced by 67.10% by the composite surfactant, which leads to a reduction of the contact angle of the plating solution from 71 to 37 in degree, and a decrease of the salt film capacity of the plating agent by 29.10%, an indication that they are both superior to the addition of the single surfactant. And the metallographic microscope shows that the salt film formed by the plating solution added with the composite surfactant is more homogeneous and compact in distribution.