A study was carried to investigate the effects of precipitation-acidified water of Donghu Lake on the survival and reproduction of Brachionus bidentata under the condition of individual cul-ture. The experiment was conducted at 28℃ in a photoperial (L:D = 18:6) with light intensity about 500 lx. rhe rotifers were fed with ChLorella pyronoidosa at a density of 6. 0 X 10⁶cells · mL^-1，and the mediums were exchanged once twelve hours. The results show that when the roti-fers were cultured in unacidified water (pH8.4) of Donghu lake, the percentage of mictic females and the mean number of amictic eggs were 8.33% and 13.909, respectively; The intrinsic rate of the population was 0.076015 h^-1. Compared with the above results, when the media was acidi-fied to pH 6.5, 5.5 or 4.5，the numbers of amictic eggs increased to 18.778, 18.167 and 15.5 ind.，respectively; but decreased to 12.083 ind. at pH 3.5. The intrinsic rates of the populations at pH 5. 5 and 3. 5 increased to 0.08901 and 0.079684 h^-1, and no mictic females appeared, re-spectively. At pH 6.5 and 4.5, the intrinsic rates decreased to 0.069258 and 0.07354 h^-1, bui the percentages of mictic females increased to 25% and 16.67%, respectively. Between pH 6.5 and pH 3.5，Brachionus bidentata was acid tolerant.