A molten salt thermal storage heater comprises a tank body, a molten salt temperature measurement device, a molten salt adding hole, a molten salt liquid level measurement device and an atmosphere vent hole welded on the top of the tank body, wherein molten salt is disposed inside the tank body, a resistance heater auto-control system is disposed inside the molten salt, the resistance heater auto-control system comprises a high-sensitivity molten salt temperature detection component, a PLC programmable controller, frequency-converting control of a feed pump and an auto-switching component used in thermal storage and thermal discharge of a molten salt thermal storage system, a heat exchange coil pipe is disposed inside the molten salt of the tank body, and an inlet and an outlet of the heat exchange coil pipe respectively pass through the middle and the top of the tank body. The device provided by the invention perfectively places the heat exchange coil pipe inside a thermal storage medium and gets rid of necessary dependency on using air as a heat-transfer fluid, so as to realize direct heat exchange between the thermal storage medium and steam or hot water. In this way, a heat transfer coefficient and system thermal efficiency are increased to the optimal level, equipment volume is reduced greatly, equipment losses are also reduced, and social and economic benefits become better.