A new low order model is developed for biped locomotion system having five links by using predominant modes when local feedback is considered. It is shown that these predominant modes are not influenced by the coefficient of local feedback. By computer simulation, this low order model has been proved to provide good approximation for the original high order system especially with respect to the center of gravity and the angular momentum of the biped system. These properties are most important for the low order model of dynamical walking. Since the model is very simple and accurate, it can be used as the model for deciding global strategy of multilevel control.