Hot dip plating is a widely used metal surface treatment process, which can provide protection and enhancement of metal surfaces and is suitable for electric power fields. The surface of hot-dip Galfan coatings was prepared with lanthanum salt conversion film. A comprehensive investigation was conducted using various characterization techniques, including scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Additionally, the corrosion resistance of the film was studied through neutral salt spray tests, electrochemical polarization analysis, and electrochemical impedance spectroscopy, and the optimal film-forming time was determined. Based on the above research, it can be concluded that lanthanum salt conversion films significantly enhance the corrosion resistance of hot-dip Galfan coatings, particularly in transmission and transformation engineering. This contributes to further improving the performance and stability of the coatings.