With the development of the economy and the improvement of people's living standards, more and more people start to pay attention to health and exercise, and the smart bracelet is born. The designed smart bracelet in this paper can collect data such as heart rate, exercise, temperature, humidity, altitude, atmospheric pressure, and light intensity in the current environment. The collected data are processed by the STM32F103C8T6 controller. Then the processed data is displayed in the OLED display module. In addition, the corresponding data can be uploaded to the mobile phone for real-time display through the Bluetooth communication module. The test results show that the system is stable and reliable.