Magnesium alloys are used widely because of its good performance. However, its practical application is restricted by low corrosion resistance. In this study, the effects of corrosion time and NaCl concentration on the corrosion behavior of AZ61 magnesium alloy were investigated from the corrosion morphology and the corrosion rate. These results have displayed that the corrosion rate of AZ61 magnesium alloy decreases with the increasing etching time. Meanwhile, the corrosion rate of AZ61 magnesium alloy increases with the increasing sodium chloride concentration. This is mainly because that the Cl- ion in the solution destroys the protective film on the surface of magnesium alloy and the high Cl- ion concentration accelerates the corrosion rate.