The utility model relates to an automatic water temperature control system, in particular to a stable, reliable and practical automatic water temperature control system. A single-chip microcomputer is used for the real-time acquisition and control of temperature; after a temperature is set, the automatic water temperature control system can regulate the water temperature automatically without manual monitoring. The automatic water temperature control system comprises a temperature sensing part, an Analog to digital (A/D) switching circuit part, a single-chip microcomputer control part, a temperature setting part, a temperature display part and an electric furnace heating part. In the utility model, the single-chip microcomputer control part is used for the real-time acquisition and control of temperature; temperature signal is acquired by a sensor; after the temperature signal goes through an analog-to-digital conversion, the temperature volume turns into the data volume; the single-chip microcomputer then compares the data volume with the needed set temperature, thereby controlling the on-off of a solid-state relay and deciding whether the electric furnace works or not; and finally the real temperature being the same with the set temperature is ensured and the temperature is kept.