Abstract: Vehicle emitted particulate matters is an important source for urban atmospheric PM_2.5. Gasoline direct injection（GDI） engines can reduce fuel consumption and CO2 emissions, and it would become more and more popular in the near future. The large amount of particle emission by GDI engine should take the public attention. Organic matter（OM） is one of the main components of atmospheric particulate matters, which has important health and climate effects. Particulate organic matter（POM）, the quantifiable part of OM, is good source indicators for source identification. The characteristics of POM component, emission factors and source profile were investigated from GDI engine, particularly focused on the effect of engine speed, load and the catalyst. Results show that POM recognized and quantified in this research account for 14%~56% of organic matters, and 7%~44% of total PM_2.5 mass concentration. PAHs, n-alkanes, n-alkanoic acids, aromatic acids and dicarboxylic acids are the main components of POM. At low and median engine speed, with the increase of engine load, POM firstly decreases and then gradually increases,while it show an increasing trend with the increase of load in high engine speed. Three-way catalyst（TWC） decreases the POM emission by 19%~64%. The POM source profile of China differs a lot from foreign source profile. It’s quite urgent to collect our own gasoline vehicle emitted samples and get the actual POM source profile in order to acquire the precise result of source apportionment.