Potentiodynamic polarization measurement was used to study effects of temperature, Cl^- concentration and pH on the electrochemical behavior of NiTi shape memory alloy （SMA）in the synthetic saliva according to the orthogonal testing method. The results showed that temperature, Cl^- concentration and pH had great influence on the pitting behavior of NiTi. The breakdown potential was most negative at 25℃, and it increased with the increase of temperature. The breakdown potential kept in high level when the Cl^- concentration was not more than 0.1 tool/L, while it dropped sharply with the continuous increase of Cl^- concentration. The breakdown potential was highest at the solution of pH 6.0.