Magnesium alloy is a common lightweight metal structural material，but its corrosion-prone property limit its wide application in industry. Hydrotalcite can provideeffective protection for magnesium alloys due to the properties of super adsorption capacity andanion exchangeability. In this paper，the research progress of in-situ growth of hydrotalcite in magnesium alloys was reviewed，including film formation process and mechanism，corrosion protection mechanism and application in anticorrosive coating for magnesium alloy，and the future development was prospected. At present，the commonly used preparation methods include in-situ growth，two-step method，anion exchange method and electrodeposition. The in-situ growth method is simple，but more by-products will be produced. The in-situ growth of hydrotalcite can be achieved by two-step method and anion replacement method by controllingreaction conditions and adjusting solution composition，and better coating quality and performance can be obtained. Electrodeposition is efficient and rapid，but the adhesion of the prepared coating needs to be improved. There are four film formation mechanisms for hydrotalcite film formation，and hydrotalcite tends to nucleate preferentially near the secondphase and at defects. And the corrosion protection mechanism of hydrotalcite coating could besummarized as shielding，adsorption of ion and self-healing.