Abstract: With the acceleration urbanization process，the quality of urban aquifer groundwater is gradually becoming worse． An important metropolis in North China was selected as the study object． The sptio-temporal variability properties of total hardness of aquifer groundwater at four time points( 1980， 1990， 2000 and 2010) were analyzed based on ArcGIS． The results showed that during 1980—2010，the phreatic aquifer area with high concentration of total hardness increased greatly in research area，and the worse trend of groundwater was very obvious． The old city zone went through two phases: The rapid increase during 1980—1990 and stable status with slight decline after 1990． For the extended area of the city，the total hardness in the phreatic aquifer generally presented sluggish early and quick later increasing trend as a whole．