The invention provides a fault processing method based on task scheduling aiming at safety critical operating systems. The fault processing method not only can be used for isolating the faults that occur in software operation and avoiding the faults from spreading, but also can be used for processing the faults and restoring the system functions according to strategies preset by users when the faults occur; when a task in a scheduling operation fails, the processing and recovery of this task fault should not affect the normal operation of other tasks in order to ensure the certainty of the task execution time; specific fault processing tasks are assigned to each user task; when a task fails during operation, an operating system kernel will schedule the corresponding fault processing task to occupy the original time slice; and in the time planning and scheduling process, such fault processing tasks are also specially processed to ensure that the operation time of other normal user tasks cannot be affected during processing of the task faults.