The electrochemical behavior of NiCoCr alloy codeposition in citric acid bath was studied, by using linear potential sweep, cyclic voltammetry and A.C. impedance. In the meantime, the surface morphology and the structure of the coatings were characterized by scanning electron microscope (SEM) and Xray diffraction (XRD). The results show that Cr3+,Ni2+ and Co2+ mutually promotes the discharge and accelerates the codeposition, the deposition of Co is anomalous. When the mass concentration of the additive and the saccharin is 10 g/L and 1 g/L respectively, the pH value is 2.5, and the plating temperature is 30 ℃, the cathode polarization is stronger, which helps to obtain NiCoCr alloy coating with high chromium content. The Ni-Co-Cr alloy coating is an amorphous structure, having a bright surface.