Abstract: Individual particle analysis was developed to study the morphology, internal structure, mixing state and surface properties of PM_2.5. Individual particles of the PM_2.5 emitted by gasoline vehicles on the chassis dynamometer using the Beijing driving cycle were characterized by transmission electron microscopy coupled with energy-dispersive X-ray spectrometry. The different vehicles types, powered by gasoline direct injection（GDI） engine and port fuel injection（PFI） engine, were tested in order to understand how the different driving conditions affect particulate emissions. As a result, a total of six types of individual particles are classified, including soot, spherical organic particles, Ca-rich particles, S-rich particles, Mn-rich particles, and Fe-rich particles, with the spherical organic particles, soot, and Ca-rich particles to be the predominant types. The emission characteristics are different under different vehicle driving conditions, i.e., the cold start phase and the steady speed phase. For the GDI gasoline vehicles, the particles emitted in the cold start phase has a higher relative percentage of soot and a lower relative percentage of spherical organic particles than those in the steady speed phase. For both the steady speed phase and the cold start phase, the relative percentage of soot particles is higher, the relative percentage of the spherical organic particles is lower in the PM_2.5 emitted by GDI vehicles than those emitted by PFI vehicles.