Abstract: The stomatal diffusive resistance of plants has close relation with the particle pollution in the environment. We can even use this physiological index to indicate the degree of particle pollution in the environment and to select species which have strong resistance to pollutants and consume less water.The results of research show that the degree of stomata diffusive resistance differs in different areas. In Tianjin it is in the following order: the Smeltery area (a polluted heavy-industry area)>the Water Park area (a sight-seeing area)>the Quanyechang area (a business area) >the outskirts of the Chemical Works (a chemical polluted area)>the Panshan area(a clean area). In Beijing the order is: the Sleeping Buddha Temple-Cherry Vale area(a sight-seeing area)>the Dongdan area(a heavy traffic area)>the Capital Iron and Steel Works area(a polluted heavy industry area).The reasons for the difference are not only concerned with industrial pollution, but also with the activities of the people in the two cities, for example, the heavy-industry areas in both cities are heavily polluted by dusts in the air and the stomatal diffusive resistance of plants, becomes higher, but it is lower in the Capital Iron and Steel Works area in Beijing, it is than in the Smeltery area in Tianjin, because the leaves of trees are often washed with watered in the former. In parks and business areas a large crowds of people may cause the raising of dusts, which also results in higher stomatal diffusive resistance. The results of research also show that when dusts in the air would increase, the stomatal diffusive resistance of plants increases and reduce the rate of transpiration, becomes smaller correspondingly