Daiya River flows through Nikko and Imaichi city Tochigi Pref. and joins Kinu River. In Daiya River, Sabo works (sabo dams and channel works) started at 1918, so that the hazards of disaster at downstream decreased and the inhabitable environment for fishes improved because of stability channel conditions. This paper reports the result of a study about inhabitable environmental conditions for fish and fishway hydraulic conditions, and fishway structure in planning of fishways on Daiya River channel works.