Abstarct: Sarab Niloofar is located in 25 km north west of the Kermanshah city in south flank of Kumajar Mountain. Mountain Kumajar composed mainly from limestone laxyers of Mesozoic. In order to evaluate the factors affecting the Sarab Niloofar flow rate, the physical and chemical characteristics of Sarab Niloofar spring including electrical conductivity, water temperature, pH and the concentrations of major cations and anions of water were measured during the water year 2009- 2010. The quality characteristics of water in S. N. and gw in alluvial aquifers adjusent to the karstic aq. Feeding the S. N. Were compared using double mass plotting. The obtained results indicate that the origin of water alluvial aq. is the same. Moreover, The water level changes in alluvial aquifers adjacent to the karstic aquifer feeding Sarab Niloofar was evaluated. It is noted that the groundwater level in the aquifer, especially in low rainfall years, due to heavy pumping without constantly falling down is now. This in turn led to the karstic aquifer discharge into the adjusent alluvial aquifers. The equipotential of alluvial aquifers confirm the above. Therefore, baxsed on the above mentioned, it may be argued that in addition to the effect of rainfall, the discharging of karstic aq. Feeding the S. N. into adjusent allu. aq. is the most important reason for reducing the discharge of Sarab Niloofar recent years.