The invention discloses a no-water cleaning device of a central air-conditioning evaporator. The no-water cleaning device comprises a steam cleaning assembly, a detergent spraying assembly, a belt wheel driving assembly and a gantry-shaped bracket, wherein the steam cleaning assembly comprises a steam generator, a rigid steam delivery pipe and a steam conveying hose; the rigid steam conveying pipe is provided with a plurality of high-pressure steam shower nozzles in parallel along an axial direction. When the no-water cleaning device is used for cleaning, firstly, the belt wheel driving assembly is used for driving a rigid detergent conveying pipe to vertically move along an air conditioning external unit, and detergent output from a water pump is sprayed into a cooling fin of the air-conditioning evaporator in an atomization way by the high-pressure atomizing shower nozzles; then, steam is generated by the steam generator, the steam is sprayed into cooling fins of the air-conditioning evaporator through the high-pressure steam shower nozzles, the cooling fins of the air-conditioning evaporator are cleaned by steam flow to avoid water resource waste, and in addition, bacteria on the cooling fins of the air-conditioning evaporator can be killed by steam cleaning to improve the cleanness of air conditioning air; meanwhile, a cleaning process is automatically finished, and the no-water cleaning device has the advantages of convenience in operation and high working efficiency.