The invention discloses an automatic control device for preventing heat loss of solar heat collector. The device comprises a water supply pipe, a floating ball valve, a water supply tank, an outlet pipe I, an outlet pipe II, an incubator, a heat collector, a temperature sensor I, a wire, a valve I, a valve II, a valve III, a solenoid valve, a temperature sensor II, a single chip microcomputer, a comparator, a solar power plant, a water pipe I and a water pipe II. The present invention reduces the loss of water heat by automated control; the water temperature is kept at a higher temperature, which is convenient and flexible to operate. The device absorbs heat from the solar panel and then converts it into electric energy to supply power to the electric equipment of the invention, which embodies the environmental protection concept of the solar water heater. The use of solar energy not only brings good social and environmental benefits, but also has obvious economic value. The inventioncan better collect heat, can be applied to different pipelines, and has broad application prospects in the industry.