Abstract: Three sample plots, which were Xiaotianchi (Alt. 1800 m), Tree Line (Alt. 2000 m) and Tianwenfeng (Alt. 2325 m), were selected from the north slop of ChangBai Mountain located on the Southeastern of Jilin Province. Net photosynthesis rate (Pn) and transpiration rate (Tr) of Rhodiola sachalinensis in three simple plots were measured, furthermore appear quantum yield (AQY) and water use efficiency (WUE) also were calculated correspondingly. The result showed Pn and Tr in Tianwenfeng plot were the highest, the second was in Tree Line plot, and the lowest was in Xiaotianchi plot. However AQY and WUE displayed the reverse trend, which of Xiaotianchi plot presented the highest value, Tree Line plot was the second and Tianwenfeng plot was the lowest.

Key words: Rhodiola sachalinensis, Gas exchange, ChangBai Mountain