Energy-saving water mixing heating system and heating control method

The invention discloses an energy-saving water mixing heating system and a heating control method, and belongs to the technical field of heating. The energy-saving water mixing heating system comprises a control system, a heat source supply unit, a temperature and pressure adjusting unit, a constant-pressure coupling temperature control purification unit, a climate compensation adjusting unit and a heating terminal; and the temperature and pressure adjusting unit comprises a first dirt removing device, a first variable frequency pump, an electric adjusting valve and an opening and closing valve, the climate compensation adjusting unit comprises a variable frequency pump set, and the flow of secondary water supply is adjusted through the power of the variable frequency pump set to supplement lost heat energy in a conveying pipe network. Secondary return water and primary inlet water are mixed, the temperature of the mixed water reaches 45-60 DEG C, the temperature of the secondary inlet water is balanced by ad