Abstract: The host in a modern airborne system of digital signal processing（DSP） requires rigorous real-time constraints It carries out important functions including real-time storing, display and control A real-time computation model is presented, which is based on a kind of technique of real-time Linux The model focuses on the speciality of an airborne DSP system and its detail requirements for real-time computation It is combined with the real-time support of operating system layer and implements a complete running environment including the real-time scheduling of multi-task, the cooperation of hard real-time tasks and soft real-time tasks, and the real-time event-driven mechanism Compared with the techniques based on time-sharing operating systems, the model can achieve more stable real-time performance and higher utilization rate of computation resource; compared with the techniques based on real-time operating systems under strict licenses, its application development is more flexible and easy, and the software cost is lower