Groundwater hydrochemical type is the characterization of water chemical composition and environment, as well as an important part of groundwater quality assessment. The monitoring data of groundwater quality in handan city are analyzed and classified according to O.A.Arliekin classification method. On the basis of groundwater hydrochemical type, the pollution reasons are analyzed. The results show that total dissolved solids, total hardness, chloride, sulfate, ammonia nitrogen and fluoride, etc. are the main causes of pollution.