The utility model provides an electric heating system based on composite phase change heat storage. The system comprises an electrode boiler, a heat exchanger and a heat using end, the electrode boiler is connected with the heat exchanger through a first circulating pipeline; the heat exchanger is connected with the heat using end through a second circulating pipeline; a heat medium generated by the electrode boiler enters the heat exchanger; the second circulation pipeline is further provided with a heat storage tank body, the heat storage tank body is connected with the heat using end in parallel, and a heat exchange coil pipe and a phase change heat storage material with which the periphery of the heat exchange coil pipe is filled are arranged in the heat storage tank body. The cold medium heated by the heat exchanger can flow through the heat exchange coil to transfer heat to the phase change heat storage material for storage; and when the electrode boiler does not generate the heat medium, the cold medium from the hot end flows through the heat exchange coil in the heat storage tank body to exchange heat with the phase change heat storage material, and the heated cold medium is used as a heat source to be conveyed to the hot end again for heat supply.