In terms of the design of Traditional Embedded Real-time Operating System(ERTOS),the authors make use of the integration and big Kernel structure,which has the limitation in some aspects,such as the retractable,portable,supportable for hardware platform with new structure and open for interface standard and so on.Based on the analysis of RTOS,a sort of design model of embedded multitasking real-time operating system is proposed.First,the hardware(abstract) layer and operating system kernel are studied.Then,the highly scalable,real-time,transplantable and application programming preface design of ERTOS are presented.This design model takes use of the hardware Bard Support Package(BSP) to support the transplanting in sorts of OEM board or hardware system board,therefore solves the questions in traditional system,and last meets the current need for ERTOS.