In studies of groundwater, the issue of quality as well as quantity has particular importance, and as long as conditions of groundwater quality and quantity in different dimensions such issues are not analyzed, it cannot explain the general characteristics of the aquifer. In this study, to investigate the heavy metal pollution in Karaj plain, fi rst, from 59 selected source of plains were sampled and the samples were analyzed using atomic absorption. Map of the metal pollution refers to segregation were prepared. After the analysis conducted on selected samples of Karaj plain, concentration maps for heavy metal cadmium, lead, copper, cobalt was prepared for seasons to seasons probe and low-water of plain. According to classical statistics, as well as the results statistically signifi cant difference between the stations were obtained in terms of the concentration of these elements. The results showed that there are significant differences between the two seasons. In view of the heavy metals concentration maps of the southern part of the plain interpolation sampling points was observed in terms of emissions is much higher than the average standard of the World Health Organization. Stations located in the southern plains, such as Safar Abad Fashafouiyeh, Mahmoud Abad, Ghanbar Abad, Ghamsar, Kahrizak, Hesar-e Chupan and etc. in all the elements in this study were plain compared to the upstream areas of concentration and excessive pollution. But certainly in the long-term trend of groundwater contamination and no space will be followed by many environmental risks.