In this paper a global optimization method (dynamic programming) is used to find the optimal power management in hybrid electric city bus for the objective to reduce the fuel consumption. Knowing that when using a global optimization method the results cannot be used in real-time control; because we need to know the entire vehicle speed in advance to perform the optimization, but in spite of that this method is very useful to make a benchmark for hybrid electric city buses fuel economy and to judge the effectiveness and improve real-time control strategies. Finally results of optimal power management are shown and discussed.