The invention discloses a single-tank molten salt heat accumulating type electric heating steam boiler. The single-tank molten salt heat accumulating type electric heating steam boiler comprises a molten salt heat accumulating tank, a steam generator and an electric heating furnace, wherein a heating circulating pump and a heat exchange circulating pump are mounted at the top of the molten salt heat accumulating tank; the electric heating furnace, the heating circulating pump and the molten salt heat accumulating tank are connected to form one molten salt flow circulating system; the steam generator is on a molten salt mixing tank; and the molten salt mixing tank, the heat exchange circulating pump and the molten salt heat accumulating tank are connected to form one molten salt flow circulating system. According to the single-tank molten salt heat accumulating type electric heating steam boiler, a single-tank molten salt heat accumulating technology with low cost and small volume is adopted, and the defect that a traditional heat accumulating type electric heating steam boiler is high in construction cost and large in volume is overcome; and the molten salt mixing tank is adopted, a relatively stable temperature environment is created for molten salt-water/steam heat exchange, the heat exchange load fluctuation problem in the single-tank molten salt heat accumulating technology is solved, various coal-fired boilers outputting steam are effectively replaced, and the increasingly serious environmental pollution problem is relieved.