To research influence of silt deposition and sand deposition on Cynodon dactylon population in low water-level-fluctuating zone of Three Gorges reservoir during 172m water accumulation, C. dactylon populations in Changshou area were studied in 2009. Results showed that both silt deposition and sand deposition significantly promote C. dactylon buds to germinate, but inhibited buds formation and growth of seedlings. And the inhibition of the former was significantly greater than the latter. Silt deposition made total buds number, stem length and stem width of germination seedling be 65.4% (P <0.05), 97.0% (P <0.05), 31.2% (P <0.05) lower than the control, respectively. And sand deposition made the aforementioned parameters be 17.1% (P <0.05), 21.2% (P <0.05), 1.0% (P> 0.05) lower than the control, respectively. Then, C. dactylon, buried by silt was transplanted, respectively covered by 12cm thick silt and sand. After 40 days, germinating buds of the control group and S’d Group (covered by sand) had developed ramets on the ground, and germinating buds of S’l group (covered by silt) couldn’t penetrate the covering layer and develop ramets. Germination rate of S’1 group was significantly higher than the control and S’d group, but stem length and node number of its germinating seedlings were significantly lower than the control. They were 30.3% (P <0.01) and 80.4% (P <0.05) of the control, respectively. Stem length, node number, leaf number, leaf length and leaf width of S’d Group’s ramets were significantly more than those of the control, and their added values were 87.9% (P <0.05), 53.0% (P <0.05), 24.2 % (P <0.05), 23.4% (P <0.05) and 24.1% (P <0.05), respectively. Fresh mass, dry mass and ratio of dry-and-fresh mass of S’1 Group’s seedlings were 83.3% (P <0.01), 86.2% (P <0.01), 15.8% (P <0.05) lower than the control, respectively. And them of S’d Group’s seedlings were 76.8% (P <0.01), 110.1% (P <0.01), 20.0% (P <0.05) higher compared with the control, respectively. It indicated that buds of C. dactylon, buried by a large number of silts, still had strong potential for germination and growth during 172m water accumulation of Three Gorges Reservoir. Therefore, C. dactylon, in low water-level-fluctuating zone, has a strong ability to adapt sand deposition. but it has lower adaptive capacity for soil deposition, so that silt deposition is one of the main influencing factors of C. dactylon populations restoration in low wate-level-fluctuating zone of Three Gorges Reservoir.