The invention discloses a cleaning sterilization system. The cleaning sterilization system is provided with a fluid circuit system and an atomizing system at the same time. Through control by an electromagnetic valve, the fluid circuit system or the atomizing system can form a passage. When the fluid circuit system is started, a spray gun sprays out fluid, and the system is in a cleaning or rinsing mode. When the atomizing system is started, atomized fluid is sprayed out, and the system is in a mist washing or atomizing disinfection mode. Users can select the using modes according to the actual situations of target objects, the flexibility is high, the application range is widened and the cleaning sterilization system is practical and convenient to use. The invention further discloses a multifunctional air-conditioner cleaning machine. The structure is simple. As for a vehicle with an air-conditioner filter element or a blower resistor or an air blower capable of being removed, the fluid circuit system is started to use the spray gun for cleaning. As for a vehicle with a blower resistor or an air blower not capable of being removed conveniently, the atomizing system is started to use an atomizer for cleaning. The multifunctional air-conditioner cleaning machine is flexible, convenient to use and suitable for more vehicles.