To better understand the carbohydrates of timberline trees, and to obtain basic data to study the physiological and ecological responses, and dynamic changes of trees under global climate change, five-year-old Picea balfouriana seedlings were selected as experimental materials to study the effects of different soil temperatures and moisture treatments on their biomass and non-structural carbohydrate (NSC) concentrations. A nested design was used in a walk-in artificial climate chamber to set five treatments for soil temperature at (2, 7, 12, 17, and 22 ℃ and three for soil moisture conditions (drought, normal moisture, and saturated moisture), respectively. Each of the nine seedlings were given the same treatment; totaling 135 seedlings. After four months, their biomass, and concentrations of soluble sugar, starch, and NSC were measured. Results showed no significant effect of soil temperature on the total biomass, but low soil temperatures significantly reduced root biomass and root to shoot ratio. Drought and saturated water stress significantly reduced root biomass and root to shoot ratio under higher soil temperatures. The concentrations of soluble sugar, starch, and NSC in different organs increased or remained unchanged with decreasing soil temperature. At soil temperatures of 2 ℃ and 7 ℃, drought significantly reduced starch and NSC concentrations in annual needles and starch concentration in annual branches, while drought and saturated water stress significantly reduced starch and NSC concentrations in the roots. Low temperatures and water stress significantly affected the distribution of aboveground and underground biomass, that allocated to photosynthetic organs increased significantly. Low temperatures did not lead to carbon limitation, and even the NSC concentrations tended to increase with decreasing soil temperatures. The results supported the "growth limit" hypothesis of the timberline in some cases. Drought stress could lead to carbon starvation of Picea balfouriana seedlings at low soil temperatures.