In the research,in order to quantified study effects of plant communities on sandy waters contained different suspended sediment(SS) concentrations in different hydraulic retention time(HRT),a step constructed wetland of emerging plants,floating-leaved plants and submerged plants which based on spatial distribution of natural layer body were constructed by aquatic marcrophytes,such as Acorus calamus,Trapa incisa,Hydrilla verticillata,Vallisneria spiralis and Myriophyllum spicatum.A comparative analysis of input SS concentrations,output SS concentrations and HRT was also done.The results were as follows:(1) The input SS concentrations are 98.69,191.76,273.13 mg/L,average of 187.76 mg/L and the output average SS concentration is 26.52 mg/L,just 51.04% of the comparison treatment;(2) The output SS concentrations increase with increase of the input SS concentrations and decrease with protracting of HRT.The regression equation is Cplant out=1.231 0.170Cin-0.356H;(3) The retained SS concentrations in the experimental water increase with increase of the input SS concentrations and decrease with protracting of HRT.The regression equation is Cplant water=1.158 0.261Cin-0.623H;(4) The sedimentations of SS in constructed wetland increase with increase of the input SS concentrations and protracting of HRT.The regression equation is Wplant=0.810Cin 0.886H-2.340;(5) In order to keep transparency condition needed by emerging plants growth of constructed wetland,the relationship between the input SS concentrations and the minimum HRT must be: Hmin=0.419 Cin-38.478(98.7< Cin <273.1).