1. The pollution grade of the Han River and Keum-Gang areas was investigated through saprobien system from April to October, 1973. 2. The 53 indicated species collected from the surveyed area were a follows: bacteria(3), schizophyceae(8), flagellatae(4), diatoms(10), cholroghyceae(6), conjugatae(4), rhizopoda(3), ciliata(5), nemertini(1), rotifera(6) and crustacea (3). 3. The pollution grade of Chungpyeong, Dooksum, and the 1st Han River bridge was oligosaprobic, α-mesosaprobic, and β-polysaprobic respectively. It is considered that the increase of pollution grade of the 1st Han River bridge was caused by the inflow of polluted water from Chunggye stream. 4. The pollution grade of Yeomchang area was indicated as β-polysaprobic and Kimpo area as α-mesosaprobic. 5. The pollution grade of three surveyed areas of Keum-Gang were β-mesosabrobic, which resembled that of Paldang.