The Emergency Department (ED) in a hospital, as its name implies, is a facility to be utilized by those who require emergency medical care. This paper introduces the longitudinal organization of the patient handling " in the Pediatric Emergency called the " Pediatric Emergency Path ". This work discusses the usa-bility of the workflow approach in order to design the patient path in the Pediatric Emergency Department (PED) in order to thwart the care complexity scheme. The goal is to optimize these paths to improve the quality of the patient handling while mastering the wait time. The development of this model was based on accurate visits made in the PED of the Regional University Hospital Center (CHRU) of Lille (France). This modeling, which has to represent most faithfully possible the reality of the PED of CHRU of Lille, is necessary. It must be enough retailed to produce an analysis allowing to identify the dysfunctions of the PED and also to propose and to estimate prevention indicators of tensions. Our survey is integrated into the French National Research Agency project, titled: " Hospital: optimization, simulation and avoidance of strain " (ANR HOST) 1 .