Objective To investigate the electrochemical-corrosion behavior of a dental cobalt-chromium (Co-Cr) alloy fabricated by selective laser melting (SLM) under conditions simulating the oral environment. Methods Co-Cr alloy specimens for dental use (cylinder, 10 mm in diameter and 3 mm in thickness) were obtained by fabrication with the same Co-Cr alloy using SLM technique (SLM group, n=5) or traditional cast technique (control group, n=5). The electrochemical-corrosion behavior of the specimens were analysed with the parameter of polarization resistance (Rp), which was examined with electrochemical impedance spectroscopy tests in an artificial saliva solution with two different pHs (before diet, 5.0; after diet, 2.5). Results At pH of 5.0, Rp values of SLM group and control group were 4.25±1.11 and 3.82±1.40 respectively, and there was no significant difference between two groups (P>0.05). At pH of 2.5, Rp values of SLM group and control group were 5.83±0.88 and 3.49±0.83 respectively, and there were significant differences between two groups (P<0.05). Conclusion Compared with traditional cast technique, dental Co-Cr alloy fabricated by SLM has better anti-corrosion behavior in acid oral environment after diet.