The invention relates to the field of waste incineration fly ash treatment, in particular to a waste incineration fly ash molten salt heat treatment system. The waste incineration fly ash molten saltheat treatment system comprises a raw material feeding system, a fly ash heat treatment system, a discharging control system, a waste heat recycling system and a smoke gas purification system. The rawmaterial feeding system comprises a molten salt storage bin, a fly ash storage bin and a supply device; the fly ash heat treatment system comprises a reaction furnace, an electric heating bar, a stirrer and a temperature controller; the discharging control system comprises a liquid level sensor, a density sensor, a constant temperature cinder ladle, a centrifugal granulator and a catcher; the waste heat recycling system comprises a heat conduction oil heat exchanger, a hot oil circulation pump and a matching pipeline; the smoke gas purification system comprises an induced draft fan and a purification device; fly ash resource recycling and detoxification treatment is achieved synchronous with fly ash molten salt heat treatment, and through tail gas purification, intelligent slag discharging and molten slag waste heat recycling, energy saving emission reduction and product deep resource utilization in the fly ash heat treatment process can be promoted.