The NaMgF3 films were fabricated on the surface of Mg-Gd-Zn-Zr magnesium alloy by TUCM. Their corrosion properties were evaluated by dripping test, electrochemical test and hydrogen evaluation test, respectively. The microstructure and chemical composition of NaMgF3 films were analyzed by SEM and EDS, respectively. The results show that the NaMgF3 particles formed by TUCM are fine. The color change time of NaMgF3 film increases with increasing the process time. Their capacitive reactance arc radius and impedance value are obviously greater than that of magnesium alloy, while their corrosion current density and average hydrogen evolution rate are significantly smaller that of magnesium alloy in SBF. The NaMgF3 film promotes the deposition of Ca and P on the surface of magnesium alloy in the SBF. The new complex film of fluoride and phosphate formed by the corrosion of NaMgF3 film in the SBF will continue to protect the magnesium alloy from the corrosion