A combined energy supply system from wind, photovoltaic and solar thermal power having a medium-based thermal storage, comprising: a first medium tank configured to store unheated medium; a second medium tank configured to store heated medium; a wind and photovoltaic power generation equipment configured for power generation; a first heater configured to heat the unheated medium in the first medium tank into the heated medium using power generated by the wind and photovoltaic power generation equipment ; a second heater configured to heat the unheated medium output by the first medium tank using a solar heat collector equipment; a heat exchanger configured to heat water to steam using the heated medium outputted by the second medium tank ; a steam generator set configured to make the steam drive a steam turbine to generate power; a power transmission equipment connected to the steam generator set ; wherein the unheated medium is output from the first medium tank , and heated by the first heater and/or the second heater to be converted into the heated medium which is stored in the second medium tank : the heated medium is then output from the second medium tank into the heat exchanger , and the steam generated by the heat exchanger drives the steam generator set to generate power; wherein an output end of the first medium tank is directly respectively connected to the first heater and the second heater by a pipeline route; and an output end of the second heater is directly respectively connected to the first heater and the second medium tank by a pipeline route, such that the unheated medium is heated by the second heater only without passing through the first heater , or is heated by the first heater only without passing through the second heater , or is heated by the second heater first and then the first heater . a first medium tank configured to store unheated medium; a second medium tank configured to store heated medium; a wind and photovoltaic power generation equipment configured for power generation; a first heater configured to heat the unheated medium in the first medium tank into the heated medium using power generated by the wind and photovoltaic power generation equipment ; a second heater configured to heat the unheated medium output by the first medium tank using a solar heat collector equipment; a heat exchanger configured to heat water to steam using the heated medium outputted by the second medium tank ; a steam generator set configured to make the steam drive a steam turbine to generate power; a power transmission equipment connected to the steam generator set ; wherein the unheated medium is output from the first medium tank , and heated by the first heater and/or the second heater to be converted into the heated medium which is stored in the second medium tank : the heated medium is then output from the second medium tank into the heat exchanger , and the steam generated by the heat exchanger drives the steam generator set to generate power; wherein an output end of the first medium tank is directly respectively connected to the first heater and the second heater by a pipeline route; and an output end of the second heater is directly respectively connected to the first heater and the second medium tank by a pipeline route, such that the unheated medium is heated by the second heater only without passing through the first heater , or is heated by the first heater only without passing through the second heater , or is heated by the second heater first and then the first heater . <EOS>