The water qualities of the south Han river investigated for 8 areas between the upper flows near the Yeo ryang to the middle flows near the Yang pyeong and also for 6 tributaries for a week from on May 31 during 1977. The value of the DO in this river have reduced gradually as the river flows were down along to the low course. But on the contrary the value of the BOD have a tendency to increase along to the low course consquentially it show a tendency to be slightly pollution. The value of hardness and Na were a little superior in these areas near the Chungju city which was many cement factories than the others upper flows and the mining of lime stone. But in the lower course from these areas these values decreasing gradually, and the pollution by the mine seweage slightly found in this area. The value of hardness and Na were especially higher in these tributaries which have polluted by the seweage of mine such as Okdong stream, Gijang stream and Golji stream than in the others streams for the many region of lime stone lies to the upper flow of south Han river. In generally, the value of pH and alkalinity in this south Han river were higher than in the north Han river.