In the drying season of Summer in 1970, the Properties of water of the Young-San river from Wol-ga-ri to Dal-ri was investigated. The temperature of water was 29∼31℃ in all of the sites and the value of pH was increasing from the area of Young-San Po∼Sa-chang of the river. The values of Cl^-, hardness and alkalinity was found about 26∼16 ppm, 32∼49 ppm and 25∼37ppm respectively from Wol-ga-ri to Sa-chang of this river and then that of Cl^- in the site of Yong-bong-ri∼Ra-ju was lowest as l6ppm. The values of Cl^-, alkalinity, hardness and pH in the sites between Myung-San and Ku-san-ri of this river were found 5,327ppm, 98ppm, 2,100 ppm, and 7.4ppm. Therefore it belongs to the brackish water from this area. The values of Cl^- and NO₃-N in this river were move 3 times and 30 times than that of the rivers in Kyung Gi Do and Kang Won Do.