The performance of Networked Control System (NCS) is not only determined by controller, but also by network QoS. In this paper, aiming at the bandwidth scheduling problem of multiple closed loop control system, an approximate linear function of continuous system performance with delay and sample period is proposed firstly, and then the optimal scheduling algorithm under both non-preemptive rate monotonic (NPRM) schedulability constraint and NCS stability constraint is proposed which is to optimize the overall performance of NCS. Moreover, an algorithm of sample periods harmonization is presented to improve the bandwidth utilization. A reservation-based schedule of non-period data is also taken into account. Finally, an integrated simulation platform based on Truetime is present, and the experimental results show that the scheme is more effective than the former ones.