Reservoirs created by damming rivers and inundating terrestrial areas can have serious effects on ecosystem structure and functions of riverine wetlands. Here, we tested the hypothesis that reservoir shorelines had similar vegetation characteristics to adjacent riverine wetlands due to propagule dispersal and examined whether vegetation distribution in reservoir shorelines was related to topographic factors. We investigated 146, 44, and 67 plots in shorelines of the Danjiangkou Reservoir, upstream and downstream wetlands, and tributary wetlands, respectively. Results revealed that reservoir shorelines had a similarity of 45% to riverine wetlands in species composition. Two-way indicator species analysis demonstrated that communities in reservoirshorelines were dominated by mesophyte species such as Cynodon dactylon and Abutilon theophrasti, while communities in riverine wetlands were largely dominated by hygrophyte species including Paspalum paspaloides, Alternanthera philoxeroides, and Polygonum hydropiper. Moreover, species diversity and percentage of perennial species in reservoir shorelines were lower than those in riverine wetlands. Canonical correspondence analysis indicated that topographic factors including landform, slope, and distance to water were important factors regulating species and community distribution in reservoir shorelines. Landform and slope also strongly influenced the species diversity of shoreline vegetation. Results from this study may contribute to a better understanding of shoreline vegetation in large subtropical reservoirs and provide information for future re-vegetation in the Danjiangkou Reservoir after damheightening.