The Trichocerca is an important and dominant species of rotifers in tropical-subtropical regions. To understand its spatial distribution in reservoirs and potential driving factors, Trichocerca assemblages were investigated monthly in riverine zone, transition zone and lacustrine zone of the Liuxihe Reservoir (Guangdong, South China) over the period of January, 2013 to December, 2014. In total, eleven species were observed in the genus. Trichocerca similis, T. cylindrica, T. pusilla and T. capucina were dominant species which have clear seasonal characteristics in wet seasons. Two-year mean total abundance was 142.9, 102.5 and 53.6 ind./L in riverine zone, transition zone and lacustrine zone, respectively, and the averaged abundances of three zones are higher in summer (May-September). The species richness and Simpson index decreased from upstream to downstream of the reservoir. The longitudinal gradient reflects the rotifer responses to change in environmental stability. Principle component analysis showed a significant tempo-spatial variation of the dominant species. Redundancy analysis demonstrated that chlorophyll-a concentration, Asplanchna abundance (a predator), and temperature+PO₄^3--P were the critical variables influencing the structure of Trichocerca assemblage in the riverine zone, transition zone and lacustrine zone, respectively. Precipitation was the potential variable influencing the structure of Trichocerca assemblage in all three zones of the reservoir.