The invention, which relates to the technical field of heat pump air conditioning, discloses a water-source heat-pump composite system. With the system, technical problem of low economy and practicability of the existing water source heat pump system in the prior art can be solved. According to the technical scheme, the composite system comprises at least two circulating water systems. Each circulating water system contains a water taking circulating pipeline, a heat exchanger, an intermediary water circulation pipeline; and the heat exchanger is connected with the water taking circulating pipeline and the intermediary water circulation pipeline. A heat pump set is connected with the intermediary water circulation pipeline of the circulating water system. Each intermediary water circulation pipeline includes a first pipeline and a second pipeline; and intermediary water inside the first pipeline flows to the heat pump set and intermediary water inside the second pipeline flows to the heat exchanger. The first pipelines of all circulating water systems are connected by a first normally-closed pipeline; and the second pipelines of all circulating water systems are connected by a second normally-closed pipeline. The provided water-source heat-pump composite system has high economy and practicability.