Abstract: The electrochemical behavior of an Al-Zn-In-Si-Ti-Sn sacrificial anode coated with backfill stone in dilute seawater was studied using electrochemical testing and galvanic corrosion testing. The results show that the charge transfer resistance (R_ct) and inductance resistance (R_L) of the Al-Zn-In-Si-Ti-Sn sacrificial anode in backfill stone coating environment were higher than those in the brackish water environment, and its corrosion current density (J_corr) in the backfill stone coating environment was significantly lower than that in the brackish water environment. Under the coverage of backfill stone, the anodic current significantly decreased, the mixing potential significantly shifted forward, and the anodic dissolution was uneven. Backfilling stone would hinder the diffusion of Cl^- and dissolved oxygen, and the covering with backfilling stone would significantly reduce the dissolution rate of the Al-Zn-In-Si-Ti-Sn sacrificial anode, resulting in uneven dissolution and ultimately a decrease in anode performance.