The community structure and biodiversity of macrozoobenthos in lower grade river—Heizhuchong stream of Hanjiang River Basin was investigated from June, 2003 to June, 2004. The results showed that the community structure and biodiversity was complex, which indicates that the ecological function of the stream goes well. Among the collected 85 species, 71 were insect species. The community structure exhibited an obvious spatial and temporal variation, Site 4 with fringe effect possessing the most species, and in February there existed 50 species, much more than those in other months. The annual dynamics of biodiversity indexes suggested that Site 1 kept more stable and Site 5 appeared more variable than those in other sites. More than 60% of the collected species could inhabit in six different microhabitats. Biodiversity in spring was much greater than that in summer, and that in summer was yel greater than that in fall. Based on Wetzel’s functional feeding group concept, 80% community species were gathering-filtering collectors. The density of the community reached its peak at 1843 ind/m² in January, and biomass attained its peak at 228.7393 g/m² in October.