Large-scale studies were carried out to see the spatial distribution of virioplankton in 15 wetlands with different trophic environments. Epifluorescence microscopy was used to detect the abundance of virioplankton. Water transparency, water temperature, pH, total nitrogen concentration, total phosphorus concentration, COD, chlorophyll a and viable bacteria concentration were also recorded. Our results indicated that viral abundance was not only correlated to bacterial density and chlorophyll a concentration （P<0.05）, but also closely correlated to COD and water temperature（P<0.01）. This in turn suggested that organic substance and water temperature should be the key factors to influence the spatial and temporal distribution of virioplankton respectively. Moreover, viral abundance was more closely correlated to bacterial density（P<0.05） than to chl a concentration（P>0.05）in eutrophic freshwater wetlands, which indicated that it was bacteriophage (but not phytoplankton virus) the dominant species of virioplankton in eutrophic freshwater wetlands.