Hot dip galvanizing has been widely used to prevent steel from corrosion. However, its anti-corrosion ability changes with the environment resulting in the change of its service life. In this paper, electrochemical characteristics of different phases in the zinc coating layer and corrosion behaviour and anti-corrosion mechanism of hot dip galvanizing in atmosphere, aqueous solution and concrete are introduced. Furthermore, its service life in different environment is described by the published data which shows that the concentrations of chloride and sulfate ions possess the greatest influence on its service life, especially the former. These results are noticeable for designers and users to pay more attention.