Abstract: The electrochemical behaviors of Ce(Ⅲ) on Mo electrodes in LiCl-KCl, NaCl-KCl and KCl molten salt were compared at different temperatures. The results show that in the high-temperature NaCl-KCl and KCl molten salt systems, since Ce(Ⅲ), Na(Ⅰ) and K(Ⅰ) have similar reduction potentials, with a large amount of matrix element co-reduction will occur, while in low-temperature LiCl-KCl Ce(Ⅲ) does not occur as described above. The reduction reaction of Ce(Ⅲ) in the LiCl-KCl molten salt system is a one-step three-electron transfer reversible reaction. The relationship between the diffusion coefficient and temperature from CV and CP is calculated respectively. The formulas are ln D=-4 341.5/T-7.97 and ln D=-4 346.6/T-7.39, the relationship between apparent reduction potential and temperature is E,*(Ce(Ⅲ)/Ce)=0.000 72T-3.650.