In order to research the harm of particle matter to human health, the TSI dust instrument, particle counter and miniature meteorological instrument were used in this paper to monitor the PM10 concentration of one typical cross road in Xi’an city. The affect factors of the PM10 concentration were also discussed. The results provided that: there is weak linear relationship between sample concentration of PM10 and wind velocity because of the complex shape of the buildings. The fine particles (<1.0μm) mainly come from vehicle emission in the cross road,and the sample concentration of PM10 has a significant relationship with the fine particles under high humidity conditions, while it has weak correlation with traffic flow. The fine particles from vehicle emission and the high humidity condition is the primary cause of the high PM10 concentration, while the temperature and airflow caused by the building shape affect the diffusion and distribution of the PM10.