Twelve filter samples were sampled monthly during a continuous 1-year campaign at a remote site, Nam Co in central Tibetan Plateau. The total aerosol concentrations ranged from 0.48 μg/m3 to 36.11 μg/m3 with the annual average of 6.74 μg/m3, reflecting a typical background level. The composition and morphology of atmospheric aerosols with size ranging from 0.5 to 10 μm were investigated using a scanning electron microscope coupled with energy dispersive X-ray analysis. Then aerosol particles were classified into 7 groups: soot, tar ball, aluminosilicates/quartz, calcium sulfate, Ca/Mg carbonate, Fe/Ti oxide, and biological particle. Aerosol optical properties from the sun photometer and the results obtained by SEM-EDX could support and verify each other, providing complementary information on aerosol characteristics at Nam Co. Two distinct types of air masses arriving at Nam Co correspond to different aerosol constituent, showing that the summer monsoon circulation may bring considerable pollution from South Asia, while the westerly flow dominated in winter is relative clean.