This paper develops a set of comprehensive factors for modeling vehicle emissions in Beijing,by using a calibrated of Mobile6.2 model in conjunction with the observed traffic volumes,the vehicle registration data from the Chi-na Statistical Yearbooks,the consumption of gas fuel and climate data of Beijing.Based on a Gauss diffusion formulation and a Matlab program,this paper develops presents the relationship between spatial distribution of vehicles and emission concentration under different conditions.The concentration maps show that the exhaust pollution is concentrated in the range of the area within 1.5 km around the ring roads;the average emission concentration is 100 times higher than the limits from the Air Quality Standard Grade 2 when taking SO 2 as an example.A comparison between the results from the model and the observed data is conducted and it is found that the relative deviation is less than 20%.