抢占式调度是RTOS的一个重要的调度策略,它保证了嵌入式系统的实时性。合理地分配任务的优先级和使用系统资源将会大大提高系统的性能。而解决优先级反转问题将保证系统共享资源的合理使用和多任务的正常运行。在对RTOS抢占式调度策略的研究的基础上,指出了什么是优先级反转,以及问题发生的原因,并给出了优先级继承和优先级封顶的解决方法。 Preemptive scheduling is an important scheduling strategy of RTOS, which guarantees the real-time performance of embedded systems. Rational distribution of task priorities and the use of system resources will greatly improve system performance. To solve the problem of priority inversion, the system will ensure the rational use of shared resources and the normal operation of multi-tasking. Based on the research of preemptive scheduling strategy of RTOS, this paper pointed out what is the priority inversion and the reason of the problem, and gave the solutions of priority inheritance and priority capping.