Abstract: The paper proposed a design method of simple real-time multitask dispatching program using software expanding interruption technology,introduced implementation of one dispatching program and four system’s dispatchings namely triggering call of software interruption,call in of hardware interruption,call out of hardware interruption and call trap,and gave corresponding program diagrams.The method has advantages such as short core programs,high efficiency and simple to use,which is suitable for application of single-chip microcomputer.