Three days were selected to study the effect of different long-distance transportation on atmospheric pollution in Taipei, China. Concentration of water-soluble anion of aerosols in Taipei was measured. Back trajectory of air masses, mass ratio and sources of water-soluble anions were analyzed. The results showed that water-soluble anion of aerosol in Taipei was composed of Cl-, NO2-, NO3- and SO42-. SO42- was the major component, which accounted for 60-90% in mass, and then following is NO3- which accounted for 9-22% in mass. SO42- and NO3- were likely from the same source. Concentration of NO2- could not be ignored. Long-distance transportation of sea-salt aerosol could decrease atmospheric pollution in Taipei. However, long-distance transportation of aerosols from coastland of China could increase atmospheric pollution in Taipei. Long-distance transportation of dust was not always increase atmospheric pollution in Taipei