Abstract: In order to reveal the community structure and spatiotemporal patterns of macrobenthos in Heilonggang-Yudong river system, benthic macroinvertebrates in Heilonggang-Yudong river system were investigated in June 2013. Biological diversity was assessed using Margalef index, Shannon-Wiener index and Pielou index. Meanwhile, clustering and factor analysis were applied to analyze the community structure. A total of 64 species, belonging to 3 phyla, 6 classes and 21 families, were identified. Among them, the aquatic insects were the most abundant. The numbers and ratios of reported species belonging to Insecta, Gastropoda, Oligochaeta, Lamellibranchia, Crustacea and Hirudinea were 34 (53.1%), 13 (20.3%), 9 (14.1%), 4 (6.2%), 3 (4.7%), and 1 (1.6%), respectively. The highest density among the macroinvertebrates was identified for chironomids in Insecta, while the biomass composition was dominated by Gastropods. The results revealed that macroinvertebrate community structure of the system was simple with low species diversity, and biomass and density distribution were not uniform. However, species in the Zhangwei New River and South Canal were rich. The analyses indicated that pollution was slight in the middle reaches of the river system, while the presence of Tubificidae in Oligochaeta in the upper and downstream reaches indicated moderate or severe water pollution.