Some problems that lowprecision, high power consumption and long operation time are still existed in ultrasonic heat meter on the current market. So the ultrasonic heat meter based on STM32L152 and TDCGP22 is developed. Flow, temperature and heat are measured by ultrasonic timedifference method for flow measurement and capacitor’s chargedischarge principle for temperature measurement. The designed heat meter includes flow measurement, temperature measurement, communication modules and interactive modules. Hardware circuit design and software design of the heat meter are described in detail in this paper. The experiment results show that the flowmeasurement precision error is within 1% and it can work 9 years consistently with one 19 000 mAh battery supply. The ultrasonic heat meter with battery supply has the advantages of highprecision and lowpower consumption. It has broad prospect of applications.