Next-generation vehicles which include Electric Vehicles and Hybrid Electric Vehicles are studied and expected to reduce carbon dioxide emissions. The number of small delivery hybrid trucks has increased in the commercial vehicle class. The engine load of a commercial hybrid truck is reduced by using an electric motor. Fuel economy of the hybrid truck is improved with the assist. On the other hand, exhaust-gas temperature is decreased, and it has a negative effect on the purification performance of aftertreatment system.In this report, the fuel performance and emission gas characteristics of marketed small hybrid trucks were surveyed using the chassis dynamometer test system. Next, the relationship between the fuel performance and emission gas characteristics during the traveling of various hybrid trucks was checked and the new hybrid control aiming at both improvement of fuel economy and reduction of the emission gas at a time was reviewed by using the Hybrid powertrain test bed system.