In April of 2008 water samples were collected from four different rivers, which were Wuchao gang River, Henggang River, Chaoyang River and Caoyanghuanbang River. During the sampling the physical and chemical parameters were measured. The abundance and the diversity of the bacteria of these four rivers were studied. The results showed that the population level increased in the more severely polluted river while the bacterial diversity decreased; the bacterial community structure was also affected by the different ecological conditions of each sampling spot. The bacterial composition and abundance was closely related to the water quality in the river.