Abstract: In order to study how to strengthen the real-time support of Linux operating system, some weaknesses of the process scheduler of the 2.4 kernel are discusses. Owing to the lack of real-time support, the system can not guarantee that the real-time tasks be responded and scheduled in time. The 2.4 kernel is not e-nough to the multiprocessor support. This paper analyses the principles and implementing details of process scheduler in the 2.6 kernel. Compared with the 2.4 kernel, the 2.6 kernel strengthens the support of real-time tasks and multiprocessor environment, implements the O(1) scheduling algorithm and preeption. The article also describes some improvement in the 2.6 kernel on response time and system spending. The prominence characteristics of the 2.6 process scheduler are to support preemption and the loading balance of multiprocessor etc., so it can be used in the real-time environment.