Abstract: Some chemical parameters and phosphase activity of the overlying water in the centre of Huixian Karst Wetland were analysed by 4-time water sampling (0.5 m deep) at 7 districts (the central wetland was divided into 7 districts) (10～15 sampling points in every District) in early stage,metaphase,and late stage during the dry season from 2009 to 2010.Results of the researchsuggested that the overlying water body in Huixian Karst Wetland was in a eutrophic state of.Scale Ⅳ～Ⅴ,refered to the evaluation criteria of Taihu Lake water body.In this wetland,District Ⅲ and Ⅳ are the two largest ones and so their principal character is representative.The plants growing in these two districts dobetter in adsorption,intake or precipitation of phosphorus.But the phosphase activity of the water body in District Ⅲ is much higher than that in District Ⅳ,which shows that composition of flora species in District Ⅳ is not propitious toset free its internal phosphorus.Based on the differences in TP,SRP and phosphase activity between District Ⅲ and Ⅳ,it is suggested that the restoration of aquatic vegetation in Huixian Karst Wetland should adopt the pattern of DistricttⅣ:Cladium chinense (planted in the shore zone)-Vallisneria denseserrulata/Hydrilla verticillat/Potamogeton malaianus (in the ballow).The relationshipbetween phosphase activity and SRP is inverse proportion for the whole researched water bodies in Huixian Karst Wetland in early stage,metaphase of its dry season,which suggests that phosphase activity can work as one of the prewarning information for eutrophication tendency of the water body in this Wetland during the testing period.

Key words: Guilin Huixian Karst Wetland, water body, phosphase activity