Abstract: In order to grasp the population dynamics of plankton at different space in rotifer ponds, the species, quantity and distribution of phytoplankton and zooplankton in the three rotifer ponds in Xiamen were studied. The results showed that Chlorophyta, Cryptophyta, Bacillariophyta, Euglenophyta, Chrysophyta, Pyrrophyta and Cyanophyta were the main species of phytoplankton. There were 17 species in 15 genera of 7 phyla, among which there were 4 species of Chlorophyta in 4 genera, 2 genera of Cryptophyta in 2 genera, 4 species of Bacillariophyta in 3 genera, 1 specie of Euglenophyta in 1 genus, 2 species of Chrysophyta in 2 genera, 2 species of Pyrrophyta in 3 genera and 1 specie of Cyanophyta in 1 genera. The average biomass of phytoplankton at the early stage of the peak of rotifers was 147.64 mg·L^-1, while that at the peak of rotifers was 99.41 mg·L^-1. The diversity index of phytoplankton was 2.94 at the early stage of the peak of rotifers and 3.12 at the peak. There were 8 species of zooplankton, among which there were 4 protozoans, 2 rotifers and 2 copepods. The average biomass of zooplankton was 83.10 mg·L^-1, of which the Brachionus plicatilis was the majority, with an average biomass of 73.13 mg·L^-1 and a diversity index of zooplankton of 0.73. The measured vertical distribution of phytoplankton in the rotifer-culturing ponds was mostly dinoflagellates (such as Chrysophyceae), the number of which in the surface layer was greater than that in the bottom layer. The difference was mainly caused by the movement of dinoflagellates. The spatial distribution of rotifers was closely related to the wind, waves and dissolved oxygen.