Dongzhen Reservoir is the importantwater source for Putian City and its water quality affects the developmentof economy and the society of the city. In recentyears,the ecosystem of the reservoir has been aggravated due to the strengthened human activities. According to the field investigation and the analysis of the monitoring data of water quality,itis easy to find outthatthe major indexes of water quality increase year by year and water quality gradually declines,which brings on the shortage of pollution-induced water. The deteriorated water quality is mainly due to the massive forestexploitation by human being,which leads to severe soil erosion,increased agricultural non-pointsource pollution,strengthened human activities,tre-mendous reservoir sediment,and so on. Then the authors suggestsome comprehensive countermeasures,in-cluding strengthen of dissemination and education,developmentof eco-orchard,improvementof ecological environment,establishmentof eco-compensation mechanism,improvementof monitoring system,enhance-mentof management,and control of agricultural non-pointsource pollution.