Emergency health care services have a highly complex patient treatment system. This system is characterized by stochastic arrivals of patients which can lead in the case of activity to its services overload. In fact, the complexity of these medical exercises relays on assigning health care operations to medical staff members respecting constraints related to the uncertain environment. The objective is to minimize costs and delays and to increase the quality of care as well as patient satisfaction. In this article, a planning method is applied in the Pediatric Emergency Department of the Regional University Hospital of Lille (Northern France).The proposed approach is composed of two phases: the first one is an assignment procedure based on fuzzy logic and the second phase is based on an evolutionary method to solve the problem of medical staff scheduling. This approach improves the performance of the scheduling system in order to help physicians to better manage their organization and anticipate the overcrowding feature. This work is integrated into HOST project (Hospital: Optimization, Simulation and Crowding Avoidance) supported and financed by the French National Agency (ANR).