Abstract: The coolant of China experimental fast reactor（CEFR） is sodium, and the emergency decay heat removal system is the safety features in CEFR, which can ensure the removal of the reactor core decay heat passively by air heat exchanger when earthquake, stop of system power supply, loss of steam generator feedwater occur. The emergency decay heat removal system design temperature is 550℃, the maximum operating temperature is 516℃, all piping is double-wall structure, the medium is high temperature liquid metal sodium. Through thermal strain measurement and analysis of emergency decay heat removal system piping, we can grasp the stress and strain of this system, monitor the stress state when the system in operation.