Monitoring of the surface water qualityprovides the possibility of usingin different consumptions, and applying different ways to minimize the damage to these resources. Considering that Iran is one of the dry countries, the development of usable water resources, maintaining and improving its quality is vital. In this regard, the water quality indices can play a very important role as one of the methods for determining the degree of water pollution, due to its ease of use and the expression of results in plain and understandable language even for non-specialists. Regular river monitoring and measurement of water quality indices at certain points along the river course can provide an accurate picture of the surface water qualityregarding the pollution. The use of this method has provided useful tools to make any management decisions that have direct or indirect environmental impacts on surface waters of the country could be adopted with more awareness and the necessity of water management methods at any point will be determined. In this research, the water quality status of Karun river basin under the sub basin of Beheshtabad was studied by sampling and analyzing the quality parameters based on water quality indices (NSFWQI and IRWQISC.(Sampling of Beheshtabad River water at six stations during one year from autumn 1395 to summer 1396 (once a season) was performed and 14 parameters of river water quality including dissolved oxygen, temperature, total dissolved solids, fecal coliform, BOD 5 , nitrate, dissolved oxygen saturation percentage, electrical conductivity, COD, ammonium, phosphate, turbidity, total hardness and pH were measured. The values ??of the NSFWQI quality index were obtained in the range of 54 to 76. According to the Keywords : Water quality, NSFWQI, IRWQISC, Karoon River, Beheshtabad sub basin
