Abstract: The demand for real-time operating system （RTOS） is becoming more and more urgent because of the development of embedded computing. The new possibility is offered to meet this demand by the research of real-time support of Linux kernel. In order to make Linux a perfect RTOS, the real-time support of Linux kernel is studied and implemented through four aspects: interrupt control, real-time scheduling policy, kernel preemption and high resolution timer. In order to keep the original system function and API of Linux, the real-time part is designed into a configurable unit. The method of two phases scheduling is discussed and its aim is to support real-time scheduling policies as more as possible and extend the system＇s applicable range. At the same time, the shortcoming of the present scheme is pointed out and the development direction in the future is discussed.