Jinan is one of the most polluted mega-cities in China, which is primarily due to the high levels of PM2.s. A quantitative understanding on the sources of PM2.s is a prerequisite to control the severe pollution. In this project, 103 PM2.s samples were collected and their chemical composition, including water-soluble ions, trace metals, organice carbon, elemental carbon and organice molecular markers, were measured. Mass closure anlysis reveals that OM (29%), sulphate (18%), nitrate (10%), ammonium (9%) and geological material (9%) are the major chemical components in PM2.s in Jinan. The data were fed to both PMF and CMB models for source apportionment and uncertainty analysis. PMF and CMB have identified secondary inorganic aerosol (41%; 31%), coal burning (10%; 16%), biomass burning (20%; 17%), vehicle emission (16%; 14%) and mineral dust (10%; 6%) as the major PM2.s sources in Jinan, respectively. CMB also identified the metallurgic plant (11 %) production as a potentially important source of Jinan's PM2.s. Furtherwork needs to be done including using other source identifications such as back trajectory, chemical transport model and remote sensing. Longer sampling periods is also recommended and establishing the local source profile is vital for the source apportionment in Jinan in the near future.