Magnesium alloys are widely used as biodegradable medical biomaterials due to their density and modulus of elasticity close to that of human bone. However, too rapid degradation in the physiological environment limits their application. In this paper, the non-toxic and easy alloying properties of liquid metal gallium are utilized to make it a coating material for biomedical Mg-Nd alloys, which is used to solve the problem of the rapid degradation rate of Mg alloys. The corrosion resistance of the Ga-Mg alloy layer was investigated by in vitro immersion in simulated body fluid (SBF) and electrochemical experiments, and a microhardness tester characterized the surface hardness. In addition, the phase transformation of the Ga-Mg alloy layer was systematically investigated in combination with XRD diffraction results. The results showed that by adjusting the alloying time of Ga with Mg-Nd in liquid metal, a "retarded layer" with high hardness, stability, and good corrosion resistance was obtained. This study is expected to expand the application of Mg alloy materials in medicine.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).