The invention relates to a heating system and a heating method. The heating system comprises a heat accumulator, a circulation loop, a first bypass and a second bypass, wherein the circulation loop is composed of a condenser, a throttle valve, a solar thermal collector and a compressor connected in sequence; the first bypass is provided with a first valve and connected with a condenser outlet and a solar thermal collector inlet; the second bypass is provided with a second valve and connected with a condenser inlet and a solar thermal collector output; and the position of the solar thermal collector is lower than that of the condenser. The heating method comprises heat pipe cyclic process and compression cyclic process, which are alternately performed. In a set time period, the heat pipe cyclic process is firstly conducted; when the temperature in the heat accumulator does not reach the set temperature and the temperature in the heat accumulator does not rise or starts to drop, the compression cyclic process is carried out. The invention can effectively use solar energy and save auxiliary heating power consumption when the sun irradiance is insufficient, thereby being more applicable to utility.