It is an important and a difficult task to analyze external inputs and interactions between objects for designing and modeling a reactive system consisting of multiple object. Also the reactive system is required huge efforts on confirm it can satisfy requirements under all possible circumstances. In this paper, we build from requirements to a scenario-based specification model using LSC(Live Sequence Chart) extending MSC(Message Sequence Chart) with richer syntax and semantic. Then the reactive system model satisfying all requirements for each object in this system can be automatically created through LTL Synthesis. Finally, we propose a method of reactive system development by iterative process transforming a reactive system model to codes.