Abstract: A 21-day feeding experiment was carried out to investigate the effect of water temperature on activities of digestive protease,amylase and lipase in stomach,pyloric caeca,liver,and gut in juvenile lenok Brachymystax lenok with body weight of 11.3±0.94g cultured and fed to satiation twice（08：00,and 15：00）a day）at water temperature of ：6℃,14℃,or 22℃.The results showed that： the minimal protease activity was observed in the stomach at 22℃,significantly lower than that in the other groups（P 0.05）.The maximal activities of lipase were found in the gut and pyloric caeca at 14℃（P 0.05）.There were significantly higher activities of amylase were showed in the gut and pyloric caeca than those in the stomach and liver at 14℃ and 22℃（P 0.05）.The maximal activities of amylase were occurred in all examined digestive organs at14℃,and there were significantly lower amylase activities in the liver and gut at 6℃than that at 14℃（P 0.05）.

Key words: Brachymystax lenok, water temperature, digestive enzyme activity