Photosynthetic rate and transpiration rate on Hippophae rhamnoides sinensis and Hippophae rhamnoides were studied in different soil water conditions.It is found that photosynthetic rate and transpiration rate increase with increased soil water content.The day course of photosynthetic rate and transpiration rate is of single summit or twin summits in different soil water conditions,and time for the summit varies with soil water content.With suitable water content,the mean photosynthetic rate of the male of Hippophae rhamnoides is higher than the mean photosynthetic rate of the female of Hippophae rhamnoides.Under drought stress,the female of Hippophae rhamnoides is higher than the male.The mean photosynthetic rate of the female of Hippophae rhamnoides sinensis is higher than the mean photosynthetic rate of the male.The photosynthetic capacity of Hippophae rhamnoides is higher than that of Hippophae rhamnoides sinensis,and the mean transpiration rate of the female of Hippophae rhamnoides is higher than the mean transpiration rate of the male of Hippophae rhamnoides.The mean transpiration rate of the male and female of Hippophae rhamnoides sinensis do not have any differences.The regression analysis shows that the relationship of photosynthetic rate and transpiration rate with soil water content can be expressed by y=a+bx+cx~2.