Four different concentrations of CuO-ethylene glycol nanoparticles were prepared. The first is the nanoparticles with ethylene glycol liquid ( 50% ethylene glycol and 50% water mixture) is directly mixed，and then on the dispersing agent after ultrasonic vibration and mechanical stirring to prepare nanofluid. Finally，the nanofluid is injected into the experimental cycle system，and the experimental measurement of the heat transfer characteristics is carried out. The results show that the heat transfer effect is more obvious than that of the base fluid，and the heat transfer coefficient increases with the increase of the mass fraction of the nanofluid. When the nanofluid is cooling medium，the greater the mass fraction of nanofluid pump power loss is bigger，and when the mass fraction of nanofluid is less than 0. 50% . the heat transfer effect is not obvious. When the volume fraction of CuO-glycol nanofluid is 0. 50%，the pressure drop increased 8. 23% and the heat transfer coefficient increases by 23. 18%，its comprehensive benefit is best.