Abstract: The mullite membrane Ag/AgCl reference electrode employed for the high-temperature NaCl-KCl molten salt was prepared, and its performance were comprehensively evaluated. The results show that the initial activation time of mullite membrane Ag/AgCl reference electrode in 830 ℃ NaCl-KCl molten salt system is about 2 h. In the range of 780-880 ℃, the difference between the actual measured voltage value and the calculated value is within ±3 mV. The linear fitting of potential difference and temperature was studied and the value of r² is 0.999. The potential can obtain equilibrium within 10 min after polarization at ±10 mA for 10 s. The reference electrode with advantages of good stability, parallelism and reproducibility can be used to investigate the electrochemical behavior of chloride molten salt system.