In order to investigate the influences of Mg/Al ratios on crystal structure, anion controlled release ability and rust inhibition effect of MgAl-layered bimetallic hydroxides (MgAl-LDHs), MgAl-LDHs with Mg/Al molar ratios of 2∶1, 3∶1 and 4∶1 were synthesized by co-precipitation method. The phase composition of the synthesized samples was analyzed by XRD and FTIR. The chloride ion adsorption performance of the synthesized samples and their corrosion inhibition effect on steel bar in simulated concrete pore solution were studied by chloride ion adsorption and electrochemical experiments. The results show that with the increase of Mg/Al molar ratios from 2∶1 to 4∶1, the interlayer spacing of LDHs decreases from 0.888 nm to 0.796 nm, resulting in a decrease in the number of LDHs loaded anions and a decrease in chloride ion adsorption capacity. The critical chloride ion concentrations of Mg2Al-NO-3, Mg3Al-NO-3 and Mg4Al-NO-3 doped groups are 0.16, 0.14 and 0.14 mol/L, respectively, which are 60%, 40% and 40% higher than that of the blank group (0.10 mol/L).