West Liaohe river plain is an important food base of China, and the groundwater is the main resource of water supply. Because of the effect of industrial and domestic pollution and the application of fertilizer and pesticide in agriculture, the groundwater has been polluted to a certain extent. This article analysis of carious methods of groundwater pollution evaluation, improves the method of single factor pollution, and proposes the single index pollution standard. The author carried out the survey in the west Liaohe plain, and collected 390 groundwater samples. Every sample is tested 79 indicators(including 7 live tests). According to the date’s analysis , we choose 34 items evaluated , such as iron ,fluorine ,nitrogen and organic projects This article uses the single factor pollution index method to evaluate the groundwater pollution of the eastern west Liaohe plain and analyze the causes of groundwater pollution. According to the pollution’s classification, the author classifies the pollution distribution range, and analyzes the reasons that led to groundwater pollution. This article solves the contrast between the evaluations of regional pollution problems, it can directly reflect the regional groundwater pollution, and provide a basis for management of groundwater pollution.