Abstract: Objective： To study the effects of the fluorine ion environment on metal corrosion resistance after porcelain-fused-to-metal crown(PFM) process treatment. Methods：Specimens of gold (Au) alloy, pure titanium (Ti), cobalt chromium (CoCr)alloy, nickel chromium（NiCr）alloy, 6 pieces each, were respectively produced. Processed by simulated clinical PFM in plain artificial saliva (group A), and in artificial saliva which contained 0.2% NaF (group B). Thereby polarization curve could be drawn, and results of the corrosion potential (Ecorr) and the corrosion current density (Icorr) of the materials were acquired. Results：By comparison between group B and group A, the corrosion potential negative values of nickel chromium alloy and co-cr alloy, and pure titanium increased, and the difference was statistically significant (P < 0.05). But that of the gold alloy had no statistic difference. Between the same metal of group B and group A, the corrosion current density increased, and the difference was statistically significant (P < 0.05).Conclusions：Fluoride ions in the environment make the PFM processed metal corrosion resistance decreased, and the corrosion rate accelerated. Among all the alloys tested gold alloy and pure titanium have the strongest corrosion resistance, CoCr alloy comes the second, but NiCr alloy is the poorest.