Abstract: In order to accurately reflect the vehicle emissions change with operation condition, vehicle emission test experiment platform is established for the actual road test based on light-duty vehicle by OEM-2100. The difference of emission pollutants under different operation modes and the influence of three kinds of motor vehicles emission pollutants discharge rate caused by velocity and acceleration were analyzed. Three kinds of pollutants emission characteristics under the joint distribution of velocity and acceleration were given. The results show that emission value under accelerated condition is significantly higher than under other conditions, and cruise takes second place, followed by idle speed and slow. What's more, when the speed is in 30~50 km·h<sup<-1</sup<, the acceleration is less than or equal 0.5 m·s<sup<-2</sup<, it can achieve the best emissions performance.