Abstract: Two issues should be considered in designing a water-bath system, namely, the accuracy and sensitivity of temperature control. The sensor's accuracy directly determines the system's accuracy. The system's sensitivity is largely related with the heat source and the thermal medium. The low accuracy of traditional thermocouples leads to low accuracy of the system. The traditional heat source and thermal medium make the heat distribution uneven in the temporal and spatial domains, resulting in a low sensitivity of the system. In this paper, a system is designed with the hardware and the software combined. First of all, the single-bus temperature sensor DS18B20 is used to improve the system's accuracy. Secondly, the system's sensitivity is enhanced through utilizing the electrolyte solution heating technique. Some experiments are designed to test the system's accuracy. The results show that the system's accuracy is up to 0.05℃. Other experiments are used to test the system's sensitivity according to the electrochemical theory. The results show that the system can maintain the temperature synchronization in space and time. That is to say, the sensor can capture the system's temperature in real time.