Abstract:The emission experiments of LNG (Liquefied Natural Gas) bus and Hybrid bus on urban roads were carried out with high-precision mobile emission tester. Then the vehicles’ emission characteristics were analyzed. Experimental results show that the CO emission of the LNG vehicle is less than that of the hybrid vehicle, and NOx emissions are relatively close to each other, while the HC emission of the LNG bus is far higher than that of the hybrid bus. Three emission factors of LNG vehicle decrease with the increase of speed, but the emission rates are different with the change of speed and acceleration. Due to the mode of pure electric start and motor auxiliary accelerating of the hybrid bus, the emissions of the three pollutants achieve the least at the speed of 15-20 km/h, and CO and HC emissions reach their maximums at the acceleration of 0 while the NOx emission reach its maximum at the acceleration of around 0.5 m/s2.