With the wide application of embedded devices in the field of measurement, how to ensure the stable and reliable power supply of the measuring instruments in the absence of a fixed power has become a pressing problem in development of embedded devices. Given this issue, this paper proposes a long battery life, small size, stable performance, strong commonality of power management system. Firstly the power management system based on MCU STC12C2052AD hardware design framework is introduced. Then based on this design framework, the working principle of each module and its implementation method is analyzed. Finally, the software implementation process of the system is presented and the system test is conducted. The test results indicate that the design of this embedded devices of power management system could satisfy the design requirements and provide a good solution for the system design.