| An investigation was made on a diesel bus certified to CHINA V emission standards, and a test was conducted on the bus cycle on a heavy chassis dynamometer in China typical cities, the buses of which were fueled with diesel (D100), 5%, 10%, 20% waste cooking oil bend with diesel fuel (i.e. B5, B10, B20 respectively) to understand the emission characteristics of soluble organic fraction (SOF) and polycyclic aromatic hydrocarbons (PAHs). The results show that SOF component emitted by CHINA V bus is mainly concentrated on fine particles with size of 0.1~0.5 μm, fatty acids are mainly composed of even carbon fatty acids with 8~18 carbon atoms, as well as the alkane component’s carbon number is 16~36, the alkane component has a bimodal distribution as the number of carbon atoms increases. And the number of rings of PAHs is mainly 3rings or 4rings. Compared with diesel, the particulate matter quality, fatty acid, alkane and PAHs emission factors of CHINA V bus fueled with biodiesel reduces, the ratio of SOF in particulates increases, 3-ring PAHs declines, and the particulate matter toxicity of biodiesel is basically the same as that of diesel.