Abstract: The synthesis of γ-APT silane self-assembled monolayers (SAMs) on hot-dip galvanized steel (HDG) and the SAMs compatibility with γ-GPT silane were investigated by electrochemical impedance spectroscopy (EIS) and contact angles analysis. The results showed that the SAMs of the γ-APT silane are deposited on HDG surfaces. First, the SiOH groups of γ-APT are absorbed quickly onto the HDG surfaces to form Si-O-Zn. Then Si-O-Si covalent bonds are formed between the γ-APT silane molecules and the zinc surface, releasing water as a byproduct. The SAMs become stable and the compatibility between the SAMs and γ-GPT silane is good when HDG sheet is immersed in the silane for 10 hours. After that the SAMs is no continuity as a mishmash.