The invention discloses a solar water heater capable of preventing pipelines from being frozen in real time. The solar water heater mainly aims at solving the problems that for a traditional solar water heater in winter, water in water pipes is frozen, the water pipes are frozen and blocked, water resources are wasted, and the pipelines need to be replaced. A temperature induction device, a circulating water pump and a heat preservation expansion water tank with a heater are additionally arranged, a simple control device is effectively used, water in a solar water tank and water in the heat preservation expansion water tank with the heater alternately flow in real time, and the purpose that the pipelines are prevented from being blocked and frozen is achieved. The solar water heater comprises a solar water heater body, a temperature probe, the heat preservation expansion water tank with the heater, an electromagnetic valve, the circulating water pump, a control panel and a domestic water part. A simple control program is input into a controller in the control panel to control operation of the whole device and the stability of the solar water heater is guaranteed.