Abstract:According to monitoring datas of underground water in many years, choosing typical water source areas which have large change in water quality and complete and typical karst goundwater source, adopting the mean value autoregressive model, variation and evolution trend of water quality have been studied. It predicates the evolution trend of water quality will be bad in 2020 and 2030, the contents of key components will be the water standard Ⅳ or Ⅴ in most water source areas, the contents of most single indexes will exceed the hygienic standard for drinking water. In order to prevent the water quality deterioration, it is important to strengthen the external environment protection of water source area and regulate karst water resource quantity.