Abstract: The low carbon emissions of private electric vehicles facilitates their broad application prospects in replacing traditional energy vehicles and in reducing transportation carbon emissions. In order to accurately assess the carbon emissions of private electric vehicles relative to traditional energy vehicles, a life cycle assessment was used to establish a carbon emission accounting method based on the amount and rate of carbon emission reduction. The potential and key factors affecting carbon emission reduction of private electric vehicles in different provinces were simulated using scenario analysis. The results showed that: (1) Compared with traditional energy vehicles, private electric vehicles exhibit a larger extent of carbon emission reduction in 13 provinces, with reduction rates of 34.69%-70.69%, where thermal power generation is less dominant in energy production. In 18 provinces with energy production dominated by thermal power generation, the effect of private electric vehicles on carbon emission reduction is not prominent, and the reduction rates are as low as 3.20%-31.40%. (2) Among the various stages of the full life cycle of private electric vehicles, the fuel cycle carbon emissions in the low and medium emission reduction regions account for the highest proportion of 57.33%-80.91%, and continue to decrease with the improvement of regional carbon emission reduction. Due to the production of batteries, the most important carbon emission phase in the whole life cycle of private electric vehicles in high emission reduction regions is vehicle material cycle. (3) With regard to the factors affecting carbon emission reduction, the increase in mileage of scrapped vehicles has a significantly positive impact on the carbon emission reduction of private electric vehicles, but has little effect on the carbon emission reduction rate, and the increase of carbon emission reduction with increasing mileage of scrapped vehicles is more pronounced in provinces with good carbon emission reduction. Greater electricity consumption and vehicle weight compromise carbon emission reduction, and the electricity consumption shows a larger impact on carbon emission reduction and carbon reduction rate in provinces with poor carbon emission reduction. This research demonstrates that the promotion of private electric vehicles in China has led to carbon emission reduction, and the structure of energy production as well as vehicle weight are two key factors affecting carbon emission reduction. Thus, different provinces and regions should develop different private electric vehicle promotion methods according to local conditions.