本研究為運用前人對台灣北部大漢溪上游93~94年間生態環境調查成果，嘗試以其中四條支流調查所得鯉科(Cyprinid fishes)魚類及計畫保育之台灣產特有淡水魚類(Taiwan endemic freshwater fishes)為目標魚類(target species)，將各期調查數量加以統計並進行無因次處理(None-factorial)，以建立其水深、流速、水質及底質等四項棲地適合度曲線(HSC)，最後再予整合並與國內學者針對不同區域及目標魚類所制定之適合度曲線加以比較分析。本研究結果顯示整合後大漢溪上游鯉科魚類之最適水深介於0.49~0.90m，最適流速為0.45~0.75m/s，最適合水質為RPI積分值介於1.5內之未受污染等級，最適底質粒徑則為12.13~21.49cm；而台灣產特有淡水魚類之最適水深為0.41~0.86m，最適流速為0.28~0.70m/s，最適合水質為RPI積分值介於1.5內之未受污染等級，最適底質粒徑則為14.95~24.91cm。 This study is based on the report of the ecological environment investigation on the upstream of Da-Han River from 2004 to 2005. Four sub-branches of Da-Han River have been chosen to investigate. The target fish species are Cyprinid fishes and Taiwan endemic freshwater fishes. The study counts the quantity of each period of time and doing none-factorial methods to fit the four different habitat suitability curve regimes (water depth, flow velocity, water quality and bed material) of rivers. The result of this study is compared and analyzed with the other Suitability Curves (aim to different areas and different target fishes), which are established by scholars. The result of this study can be summarized as follows: The Cyprinid fishes in the upstream of Da-Han River, are most suitable for the range of the water depth between 0.49 to 0.9m, the most suitable range of flow velocity is 0.45 to 0.75m/s, the most suitable water quality is below 1.5 of RPI, the most suitable bottom sediments are 12.13 to 21.49cm. For Taiwan endemic freshwater fishes, the most suitable depth is 0.41~0.86m, the most suitable flow velocity is 0.28 to 0.70m/s, the most suitable water quality is below 1.5 of RPI, and the most suitable bottom sediments are 14.95 to 24.91cm.