Abstract: Feedback control is emerging in real-time operating system scheduling in recent years. In this paper, the idea of feedback control is introduced into time-sharing operating system scheduling, and a PID control based time-sharing operating system scheduling algorithm is proposed. It can adaptively adjust CPU bandwidth to overcome the dynamical uncertainty of CPU utilization and to meet the application specified distribution demands for CPU bandwidth, thus keeping the system performance in the best state. The simulation results illustrate the efficiency of the control mechanism of the PID time-sharing scheduling algorithm. Besides its compatibility with traditional time-sharing scheduling, the scheduling algorithm has good dynamic, static, and robust characters with very low scheduling overhead.