Chemical Element Balance was applied to identify sources of the aerosol particles,in the city of Xi'an and Zaoyuan,in order to display total levels of contribution of the main sources to aerosols in Shaanxi province. The results show that 35%～60% of the aerosols came from soil dusts,15%～30% from coal ash,15%～25% from limestone and 4%～15% from refined dusts. The differences between contribution of sources to aerosols are consistent with activities of human beings and industrial exhaust.