Abstract: In real-time system, task scheduling policy is the key part of kernel design.How to design task scheduling to ensure that all the tasks will be completed before its deadline is an important problem in the research on real-time operating system.Because the scheduler of RTAI has a bad performance when the system is in heavy load or overload, this article adds a Comprehensive Priority Static Schedule (CPSS) algorithm to RTAI scheduler, and improves and optimizes the RTAI scheduler.Finally, a simulator of the scheduling algorithms and a test of the scheduler are presented.The experiment has proved that improved scheduler can increase the real time Linux system.