The Problem of climate change caused by the increase of greenhouse gas CO_2 concentration attracts the world's attention. Stable carbon isotopic characteristics of CO_2 can provide strong support for the study of source and sink mechanism of CO_2. However, this needs the stable carbon isotope composition of different emission sources, specially local or regional sources as data base. The combustion of fossil fuel contributes a lot to the increase of CO_2 concentration, especially the emission of vehicles. In this study, we used laser-based isotope ratio infrared spectrometer (IRIS) to measure the delta ~(13)C characteristics of CO_2 emitted by gasoline vehicles in China, getting its stable carbon isotope composition (delta ~(13)C) of (-28.0 0.5). Carbon isotope fractionation exists in CO_2 emitted by gasoline vehicles. delta ~(13)C of CO_2 emitted by gasoline vehicles is not affected by cold start or hot start basically, but the composition of gasoline and engine combustion mode can influence delta ~(13)C of CO_2. The delta ~(18)O characteristics of CO_2 emitted by gasoline vehicles changes a lot, with more complicated isotope fractionation. The delta ~(13)C characteristics of CO_2 from combustion processes of fossil fuels can be a good indicator for fossil fuels. The delta ~(13)C of CO_2 emitted by gasoline vehicles as representative of China can be obtained from this preliminary study, providing basic foundation for the carbon emissions research in China.