Abstract: Scheduling strategy is kernel of one operating system，and directly impacts the performance of operating system.OSEK-based operating system is strict with the real-time performance.Through analyzing the preemptive scheduling strategy and task’s attribute of OSEK OS criterion，this paper presents a conversion strategy from task to function，which makes task execution like a function call，to reduce the task swapping time of the process of task execution，and to improve the task response performance and operating system real-time performance.The strategy’s validation is verified by experiments.