Abstract: A heating sterilized machine was designed, which was specially used for disinfection of nutrient solution from closed system. The following tasks were automatically realized: 1 m³/h treatment flow quantity, nutrient solution temperature to be heated up to 85～86℃ from circumstance temperature and time of 0～3 min to keep water at this high temperature. Tests showed that this machine had better killing effect for tomato wilting germs, cucumber withered germs and tomato bacteria green withered germs. And disinfection performance of this installation was stable and reliable. It was inferred that when the equipment was applied to kill these three pathogens(starting concentration is 3.9×10⁵～8.3×10⁵ cfu/mL) in nutrient solution, 75℃/90s could meet the demand of 100% sterilization rate.