The embodiment of the invention provides a printed circuit board cleaning machine, belonging to the technical field of printed circuit cleaning. The cleaning machine comprises a chassis, a master control system, a backing water treatment system, a cleaning system, a drying system, a waste water treatment system and a water detection system; the systems are all arranged in the chassis, the main control system is electrically connected with other systems and controls the operation of other systems; wherein, a water inlet and a water outlet are arranged on the backing water treatment system, the water outlet of the backing water treatment system is connected with the cleaning system, and the water outlet of the cleaning system is connected with the waste water treatment system; the drying system is connected with an air inlet of the cleaning system; the detection ends of the water detection system are respectively arranged on the water outlet ends of the backing water treatment system and the cleaning system, which are used for detecting the effluent water of the backing water treatment system and the cleaning system. The cleaning machine has the advantages of high cleaning efficiency, good cleaning effects, cleaning water saving and environmental protection.