Quality of water is gaining great importance with the rising pressure on industry's and agriculture and rise in standard living. The Karoon sub-river systems, located in the south west Iran, have been considered as an important water source for people in the area southwards. The Karoon River originals from the Zagros Mountain range and the Kohrang River joins it and form a great river called the North Karoon. We used data samples water quality (SAR, Cation+, Anion-, EC, TDS and PH) and discharge at 1983-2013 period. The results M-k test show that SAR, Cation+, Anion-, PH, EC and TDS have upper ward but discharge has downward trend at period(1982-2013). Other results show that the calculated Z element SAR, Cation+,Anion-,PH,EC and TDS are z ≥ + 1.96 that these amounts show elements have upper ward. There is enough evidence to determine that there is an upper ward trend. The calculated z discharge is -1.2 that it was ≥ - 1.96. Discharge has down ward trend. There is not enough evidence to determine that there is a downward trend. The results show that elements chemistry have upward trend but discharge has downward trend at Armand station.