This paper shows the relation of chemical forms of nutrients between river and seawaters in Kagawa prefecture and the Bisan-seto sea and the sea of Harima-nada. We obtained the following results: 1) the ratio of nitrogen of river waters was DIN:DON:PON = 63:17:20 and that of seawaters was DIN:DON:PON = 19:69:12. This means that the chemical forms of nutrients between river and seawaters were different, and 2) the ratio of phosphorus of river water was DIP:DOP:PP = 43:21:36 and that of seawaters was DIP:DOP:PP = 60:16:24.