Abstract: Operation of new energy vehicles in urban passenger transport is one of effective ways to solve environmental pol-lution.From the view of CO2 emissions,the whole process of energy production is comprehensively considered to calculate total energy consumption and total CO2 emissions of urban passenger traffic in Harbin.Limitation of calculation CO2 emissions based on Provincial Greenhouse Gas Inventory Guidelines(For Trial Implementation)is analyzed.A new computational method is de-veloped from the view of traffic users.According to traffic data including vehicle distance,fuel consumption,power consumption, and gas consumption,the total energy consumption(i.e.activity level) of urban passenger traffic is calculated,then multiplied by corresponding emission factor to calculate the amount of CO2 emissions.An extreme case that BEV vehicles completely replace gasoline or diesel fuel vehicles is simulated,the emission reduction of CO2 in urban passenger traffic which caused by BEV vehi-cles can be calculated.Influencing factors of unit energy consumption,unit power consumption,and power factors of CO2 emis-sions are analyzed.The results show that the total CO2 emissions from urban passenger transport is 29.01 million t in 2015.A-mong them,CO2 emissions of gasoline and diesel fuel vehicles is to 15.39 million t.Emission reduction of CO2 achieves to 413 000 t per year when BEV can replace all gasoline and diesel vehicles.