Abstract: By means of system analysis,an index system,centering around socio-economic pressure,water pollution load,and water environmental status,is established for evaluation of ecological impact of the socio-economic activities on the Taihu Basin.Weights of the indices of the system were computed,using AHP(analytic hierarchy process).And based on available data related to the Taihu Basin in 2005 and 2006,comprehensive evaluation of the ecology of the basin was performed with the aid of MATLAB and the approach of fuzzy pattern recognition.And finally,ecological impact of the socio-economic activities on the Taihu Basin was analyzed.Results show that the impact was enormous.Besides point-source pollution,non-point source pollution is one of the root causes of the ecological problems in the region.