Abstract: The optimization algorithm for sampling period in multi-loop networked control systems is studied.The basic sampling period is divided into different segments;the sampling period of each loop is adjusted as the multi-ples of the basic sampling period in the order of 2 and should not exceed the maximum allowable delay bound in the corresponding loop.The system scheduling condition is analyzed and the optimal sampling period of each loop can be optimally determined.The presented algorithm can realize real-time transmission of the real time periodic and sporadic data,and can minimize the utilization of non-real time message.A simulation example of a networked control system based on the CAN bus illustrates the effectiveness of the presented algorithm.