In order to evaluate the potential impact of the atmospheric pollution in Beijing by those cities which located southwest of it, the observations of PM10, NO(x) and O3 were conducted during the period of summer-autumn (Jul. 16-Oct. 15, 2009) in Beijing, Zhuozhou, Baoding and Shijiazhuang online, with the automated instruments which conform to international standards. The results showed that the principal pollutant was PM10, and the average concentration was (99 +/- 88), (121 +/- 74), (141 +/- 92) and (180 +/- 107) microg/m3, respectively. The concentration of NO(x) was (66 +/- 48), (23 +/- 14), (47 +/- 35) and (52 +/- 32) microg/m3, respectively. Ozone, the photochemical pollutant, the daily maximum concentration hourly was (107 +/- 60), (128 +/- 55), (164 +/- 61) and (120 +/- 54) microg/m3, respectively. Owing to the emission of local sources, the atmospheric PM10 pollution of Shijiazhuang was the most serious in 4 cities, in order was Baoding, Zhuozhou and Beijing. However, the average concentration of O3 in Baoding was the highest for the dual influence of Beijing and Shijiazhuang. Two episodes of heavy regional atmospheric pollution in July 2009 were analyzed with the surface meteorological data and backward trajectory model. The results suggested that the air quality in Beijing and the surrounding areas was significant influenced by the three cities of Hebei province in summer-autumn.