Abstarct: Sylakhor plain with an area of almost 800 km2 is situated between 48º 28´- 49º 30´east longtitude and 33º 15´- 44º 10´ latitude in the southeast of Borujerd. The aquifer in the study area is an unconfined aquifer and its thickness is abaut 160 m which consist of alternatively clay and sand. This aquifer is draining for agricultural usage with 1679 wells. To evaluate changes in groundwater level, average hydrograph of plain were computed drown from1376 to 1392. According to this hydrograph, due to reduced precipitation and increased exploitation in recent years, a sharp drop in the groundwater has occurred so that some shallow wells has been dried. In order to evaluate groundwater quality, sampling was performed in active wells. Electrical conductivity and pH were measured at the sampling site and the samples were sent to the laboratory for chemical analysis in order to determine the amounts of major elements such as calcium, sodium, magnesium, potassium, bicarbonate, sulfate and chloride. Given that the main direction of movement of groundwater flow in the study area is northeast-southeast but the results of chemical analysis showed that nearly the entire aquifer has a constant electrical conductivity values and doesn’t follow any particular trend. It is because, Silakhor plaine is a rather long plane which is from the northwest to the southeast and its feeding is majorly from northeastern to southwestern highlands that their path is relatively short, so there are not a lot of changes in the electrical conductivity values. Equipotential map of the plane confirms its feeding locations.By using Stiff and Piper diagrams, the type and facies of all groundwater samples are bicarbonate-calcic which indicates the high quality of the groundwater in the plain of Silakhor.