Yaw stability control is the most popular topics in the automotive field. Several studies have been done in searching the effective method in controlling yaw moment. Hence, an integration of the active front steering system (AFS) with Composite Nonlinear Feedback controller is presented in this paper. Recently, this controller has been used by a lot of researchers in controlling their system performance due to its main advantage that can be seen in transient response which demonstrate super fast tracking. An optimal CNF feedback control problem is formulated as a parameter optimization problem with performance index and restrictions on stability. To handle such restrictions and constraint, the particle swarm optimization algorithm is applied to solve parameter optimization problems.