The invention relates to a water path system of a heliostat cleaning tanker. The water path system comprises a liquid storage box, nozzles, a pressure relief passageway, a first flow and pressure regulating passageway and a second flow and pressure regulating passageway. The nozzles communicate with the liquid storage box through a pipeline. The nozzles comprise front-row nozzles and rear-row nozzles. A first control valve and a second control valve are arranged on the upstream pipeline of the front-row nozzles and the rear-row nozzles. The two ends of the pressure relief passageway, the two ends of the first flow and pressure regulating passageway and the two ends of the second flow and pressure regulating passageway communicate with a pipeline between the liquid storage box and the nozzles and the liquid storage box correspondingly, and the pressure relief passageway is provided with a third control valve; the first flow and pressure regulating passageway is provided with a fourth control valve and a throttling valve; and the second flow and pressure regulating passageway is provided with a fifth control valve and a throttling stop valve. The water path system is simple in structure, independent and common washing work can be achieved, and the water pressure of the system can be adjusted; it is ensured that the pressure and flow of the system are kept constant during independent and common washing work, and the water spraying pressure can be improved according to the cleanliness of a mirror surface to adapt to different mirror surface working conditions; and the responsespeed is high, and the heliostat surface can be washed twice.