After a presentation of the real time system analysis and design, we present the Structured Analysis for Real Time Systems, or SA-RT. This graphical design notation is focusing on analyzing the functional behaviour and information flow through a system. In fact, the modeling of the real time systems helps us to understand its working, without eliminating its complexity. Then, we present the graphic and textual formalism of the SA-RT method on the one hand and we apply this method on a practical case of an ABS braking system, on the other hand. Key words: Real time systems, SA-RT method, ABS braking system.