The leaf-litter decomposition is crucial for nutrient cycling in aquatic ecosystem,but the impact of urbanization on leaf-litter decomposition in urban streams remains to be clarified. To explore the transformation of relative contribution among leaf-litter decomposer groups and decomposition of streams with different urbanization rates,we took 3 Three Gorges Reservoir Regional urban streams with different urbanization rates as the research site,2 representative leaf-litter in riparian zones with different initial physiochemical properties were selected,and decomposition bags with 2 different mesh sizes (0.05mm and 1mm) were set in situ to carry out the experiment. The results showed that: (1) The decomposition rate of leaf-litter decreased by approx 30% in the high urbanization rate stream (the average decomposition rate of Broussonetia papyrifera and Ficus microcarpa decreased by 1/4 and 1/3),the decline of recalcitrant leaf-litter was more significant. (2) Microbial decomposers contributed over 80% to the leaf-litter breakdown across all the three streams. In the stream with high urbanization rate,the relative contribution of bacteria decomposition is greater than that of fungi; The proportion of pollution tolerant species in benthic invertebrates increased to 90%,and the shredder who played a vital role in decomposition disappeared,and the relative contribution to less recalcitrant leaf-litter and recalcitrant leaf-litter decreased by 45% and 15%. The decomposition rate did not change significantly in streams with low and medium urbanization rate,but was significantly reduced in stream with high urbanization rate. This study provided a scientific basis for elucidating the degradation mechanism behind stream leaf-litter decomposition in subtropical towns.