Abstract: To evaluate the effects of land use types (e.g. forest land, farmland, combination of forest land and farmland and urban land) within riparian zones on diatom community structure, the community structure of diatom and physical and chemical characteristics of water bodies were investigated at 38 sampling sites in the Taizi River, China. Cluster analysis of diatom communities showed that the same type of land use area exhibited relatively similar characteristics of diatom community structure. Indicator species analysis showed that the indicator species of forest were Cymbella turgida, Cymbella delicatula, Ceratoneis arcus and Gomphonema trancatum; the indicator species of farmland were M. granulate, N. linearis, Gyrosigma acuminatum and Cyclotella kuetzingiana. Canonical correspondence analysis showed that the COD_Mn, suspended solids and the total dissolved solid were the main factors influencing the diatom community structure characteristics in the Taizi River. The characteristics of diatom community showed an apparent divergence in the four land use types:the mean values of IDG and IBD were the highest in the forest, being 17.33 and 17.98 respectively. The mean values of Shannon-Wiener diversity and Pielou evenness index were the highest in farmland, being 3.37 and 0.82 respectively, and the lowest in forest, being 2.22 and 0.54 respectively. The mean values of species abundance, IBD and density were the lowest in urban land, being 11.00,9.20 and 0.71. The results indicated that land use types affect the diatom community structure by influencing environment conditions, and water quality and diatom community conditions were poor in urban land. Land use types within riparian zones significantly influence the diatom community structure in the Taizi River, which showed an obvious spatial heterogeneity. The study showed that the land use types within riparian zones might affect water environment quality and diatom community structure of the river.