Abstract: We studied the effect of Ipomoea aqucatica floating-bed on the rotifer community structure in grass carp pond from June to September in 2011. The density and biomass of rotifer, the key environmental factors in floating-bed and non-floating-bed ponds were tested. The densities of rotifer in the floating-bed pond and non-floating-bed pond were 1892 ind./L and 2255 ind./L, respectively. The densities in these two kinds of ponds were significantly different (P0.01). The biomasses of rotifer in the floating-bed pond and non-floating-bed pond were 1.535 and 1.405 mg/L, respectively. The biomasses in these two kinds of ponds were significantly different (P0.05). During the experiment, 38 species belonging to 7 families, 14 genera was detected in rotifers. Thirty-six species were detected in the floating-bed ponds rotifers, and 28 species were detected in non-floating-bed ponds. Dominant species of the two types of ponds were essentially similar, including Brachionus calyciflorus, Brachionus diversicornis, Anuraeopsis fissa, Trichocerca Pusila and Polyarthra dolichoptera. The results showed that Ipomoea aquatica floating-bed could promote the number of rotifer species significantly, improve the rotifer diversity and evenness, and inhibit the rotifers miniaturization effectively.