Abstract:The Euclidean distance model with varying weights was applied to evaluate the surface water quality based on the monitoring data derived from April 2010 to February 2011 in secondary forest catchment, eucalypt plantation catchment and rubber plantation catchment in Limu Mountain, Hainan Island. The results were compared with that of grey association analysis method, grey clustering model and fuzzy comprehensive evaluation method. The results indicated that the assessment results of surface water quality in the three types of forest catchments based on Euclidean distance model with varying weights and grey clustering model were Grade I, the assessment results of surface water quality in secondary forest catchment based on grey association analysis method and fuzzy comprehensive evaluation method were also Grade I, but besides that the assessment results of surface water quality in eucalypt plantation catchment in June 2010 and rubber plantation catchment in August 2010 based on the last two methods were Grade II, those in the remain seven months were Grade I, showing that the plantation in this area did not cause significantly negative effect on surface water.