Due to large mass and frequent start-stop, the advanced hybrid propulsion technologies enabling regenerating and reusing of significant amounts of braking energy are critical to achieving future fuel economy goals for city buses. The initial breakaway friction and inertia of the hydraulic hybrid bus can be overcome by energy that would ordinarily already have been wasted, and when running the engine, can operate in more efficient modes. Therefore energy-saving and environmental protection of hydraulic hybrid buses has important significance in application. The simulation model of series hydraulic hybrid bus is created in AMESim. The simulation results of the SHHB model show that it is very prominent in saving energy and reducing harmful emissions.