For the digital uninterruptible power system (UPS) , an embedded system control plan based on μC/OS-II is given to improve its timeliness. Through analysis of the control system’s structure and functions, the UPS system control projects are designed as duties to be dispatched by transplanting μC/OS-II on TMS320L F2407A. Some parameters and the main software list are given. The practice proves that the design in this paper improved the control system’s reliability and stability effectively.