The positive matrix factorization(PMF) method was used to apportion the sources for fine particles in Beijing. The data were obtained from four samplings from 1999 to 2000. The number of this data set was 40. The chemical compositions used in analysis include element carbon(EC), organics, SO4(2-), F-, Cl-, Fe, Ca, K, Mg, Al, Na, Zn, Mn, Ti, Pb, Ba and P. Six main sources, soil dust, construction dust, secondary source (by photochemical action), biomass burning, motor vehicle and coal burning were found.