Abstract: Species composition of Rotifera was investigated at four stations in Lake Donghu in 1991. With the improvement of the Rotifera taxonomy, some problems concerning the taxonomy of rotifers in China were discussed. Sixty nine species of rotifers, belonging to 29 genera of 19 families, are reported. Of these, 12 species are new records for China, 59 species in the water samples, and 41 species from resting eggs in the sediment. There were 31 species in both environments. Some species hatched from the resting eggs, such as Lepadella patella, Wolga spinifera, Mytilina compressa etc., were not found in the water samples in 1991, although they occurred in the lake water during 1960s.