In the research of fast reactor a sodium thermodynamic test loop was designed and commissioned. Its highest operating temperature is 700℃, after the sodium is passed the cooler, the temperature of the sodium can be reduced to 300 ℃; the sodium flow is 0.2 m3/h. The loop consists of sodium electromagnetic pump, sodium flow meter, two groups of heater, two groups of cooler, surge tank, sodium vapor trap, diffusion cold trap, sodium transportation tank, electric control panel and microprocessor. It has two experimental bypass loops for research of heat transfer In the research of fast reactor a sodium thermodynamic test loop was designed and commissioned. Its highest operating temperature is 700 ℃, after the sodium is passed the cooler, the temperature of the sodium can be reduced to 300 ℃; the sodium flow is 0.2 m3 / h. The loop consists of sodium electromagnetic pump, sodium flow meter, two groups of heater, two groups of cooler, surge tank, sodium vapor trap, diffusion cold trap, sodium transportation tank, electric control panel and microprocessor. bypass loops for research of heat transfer