The mixing of freshwater and salty water in saline playas, high dissolution of calcareous stones, agricultural activities, industrial effluents and municipal and rural waste landfills are the most important sources of groundwater threats that threat human health. In this study, 46 water samples were taken from Arak plain and their physical and chemical variables were determined. Multivariate statistical analysis including stage factor analysis on the physical, chemical and chemical variables of groundwater in Arak aquifer have an important role in distinguishing between different pollutants in the region. The stage factor analysis gave five factors in the hydrochemistry variables of Arak aquifer. In the first factor, the EC, TDS, Cl, SO4, Ca, Mg and Na variables have a natural origin, which is the mixing of saline water from Mighan playa and freshwater aquifer. In the second factor, HCO3 is a natural origin due to the dissolution of limestones in southern Arak and HNO3, originating from humans and as a result of the influence of urban absorption wells and agricultural activities. The origin of the elements in factor three and four, mainly Zn, Cu, Fe and Mn, is mainly due to industrial activities and landfill, and F, is also due to agricultural activities, i.e, the use of phosphate fertilizers. This study also showed that stage factor analysis is a suitable method for separating source of contaminants. Therefore, appropriate measures should be taken by organizations and companies to control human pollution from sources such as Arak municipal wastewater, agricultural and industrial wastewater.