In North China, how to properly deal with the relationship between vegetation and water resources is one of the key problems for the forest vegetation construction. Hence, how to construct forest vegetation with high moisture stability based on the water bearing capacity is important. Taking Platycladus orientalis and Pinus tabulaeformis, two typical artificial forests as the research object, we measured the water consumed by individual trees with lysimeter installed in Miaofeng Mountain, Beijing. On the basis of the measured data, water consumption by forest stands was revealed. We found that in sunny days diurnal variation of transpiration intensity of two kinds of individual trees appeared as a single peak curve. However, in cloudy or rainy days the transpiration rate varied significantly between the two species. Correlation analysis showed that among environmental factors, solar radiation flux, vapor pressure deficit, air temperature, soil water content and soil water potential were positively correlated with transpiration intensity, while the relative humidity was negatively correlated with transpiration intensity. By using tree sapwood area as transform scalar, based on the measured transpiration rate of sample trees, the transpiration quantity of forest stand was calculated. From June to September, transpiration by the forest stand of Pinus tabulaeformis was 321.43 mm and that of Platycladus orientalis 192.83 mm.