The invention discloses a modular quasi-elastic thermal storage indirect type solar energy heating system comprises a thermal collecting system, a heat exchanger, a user terminal and at least two modular thermal storage systems. The thermal collecting system comprises a solar collector and a heat-collecting circulating water pump. Each modular thermal storage system comprises a thermal storage water tank. Each thermal storage water tank is connected with the heat exchanger and the user terminal through corresponding valves to form a circulating passageway structure. The valves in each modular thermal storage system are not affected mutually, and the circulating passageway structure is formed between any one or more thermal storage water tank and the heat exchanger and the circulating passageway structure is formed between any one or more thermal storage water tank and the user terminal by controlling the combination of the valves in each modular thermal storage system. By the adoption of the modular quasi-elastic thermal storage indirect type solar energy heating system, the thermal collecting efficiency of the solar collector is guaranteed, the temperature of water in the thermal storage water tanks is kept relatively stable, the start time of an auxiliary heat source is shortened on the premise that the water supply temperature is guaranteed, and energy conservation performance and energy consumption efficiency of the system are improved.