In Laghouat city, groundwater is the only resource responsible for meeting drinking water needs, and given a fairly significant population growth in the study area, concerns raised about the change in quality and quantity of water in this region. This research aims to determine the current state of groundwater quality in the Barremian, Mio-Plio-Quaternary located in Laghouat city. A number of thirty-five groundwater drilling points located in this region were collected and analyzed during the low water period (August 2019) to identify the characteristics of the main physicochemical parameters, using the water quality index as an indicator to assess the groundwater quality of this study area. These parameters were integrated into the GIS software to create a spatial distribution map for each parameter. Statistical analysis of the data was performed using principal component analysis in XLSTAT 2014.5.03. The synthesis of the analyses obtained shows that these analyzed waters are very hard, The WQI calculation shows overall that 51.43% of the groundwater samples have poor quality, 48.57% of the groundwater samples have good quality. In Barremian, the TDS, EC and TH are strongly correlated with the Ca2+,Mg2+and Na+ and with the Cl-,SO42-.In Mio-plio-Quaternary, the TDS and EC are strongly correlated with the Ca2+,Na+ and K+ and with the Cl-. These values indicate that the mineralization is mainly related to sulfates and chlorides as well as other elements. The high hardness can be explained by the chemical nature of these waters and the contact with geological formations, and the intense evaporation that characterizes the arid climate of the region. The poor quality of the analyzed waters is probably due to the poor sealing of the sanitation network in this city, and the effect of wastewater discharged at the level of Oued M'zi, this deserves good monitoring and sustainable management.