Real-time systems and applications impose stringent timing constraints on critical tasks. The design of such systems are more complex than that of conventional systems, because correctness and performance, besides being key system design issues, are directly related to system feasiblility. Object-oriented application frameworks have been proposed for communication systems, distributed applications, medical imaging, and financial engineering. On the contrary, there has been relatively little work on an application framework for the design of a general real-time system. Facing the growing need for such systems, we propose a novel framework, called RTFrame, especially for real-time systems. RTFrame consists of five components: Specifier, Extractor, Scheduler, Allocator, and Generator. Within RTFrame, several design patterns have been proposed for real-time systems. Experiences of using RTFrame show a significant increase in design productivity through design reuse, and a significant decrease in design time and effort.