Sanbanxi Reservoir is a representatively deep plateau reservoir located in Guizhou Province. To investigate metazooplankton's community structure and their dynamic changes, the metazooplankton communities were investigated for the period from November 2012 to August 2013. In total, 19 rotifer species, 3 copepoda species and 7 cladocera species were recorded. Keratella valga, Keratella cochlearis, Mesocyclops, Nauplius and Bosmina longirostris were the common dominant species. The similarities of metazooplankton species composition between the three seasons were above 60%. The total abundance of metazooplankon appeared highest in wet season (575.03 ind./L), followed by the normal season (541.85 ind./L), and lowest in dry season(373.28 ind./L). In term of spatial pattern, the total abundance presented the greatest variations at dam site (from 26.62 ind./L to 245.27 ind./L), then at Jiachi site (159.80 ind./L to 224.10 ind./L), and the smallest changes at Nanjia site (from 122.56 ind./L to 169.96 ind./L). In general, the abundance in the surface was higher than that in the bottom, although with the exception that the highest abundance of the dam site was in the depth of 40 m and the highest of Jiachi site was in 30 m during dry season, the highest abundance in each sampling point appeared in the layer of 0.5-20 m with average abundance ranging from 19.03 to 45.31 ind./L in three seasons. The Shannon-Wiener index and Margalef index indicated that the water quality of Sanbanxi reservoir was of moderate pollution except for light pollution at Jiachi site and Nanjia site during level period.