Abstract: Soil respiration, which may constitute up to approximately three-quarters of the total ecosystem respiration, is a major component of the biosphere carbon cycle and plays an important role in the global carbon balance. However, there are few studies on the soil respiration in plantations of Platycladus orientalis. The respiration rate (R_S), temperature (T) and volumetric water content (VWC) of soil were measured for two years in a mature plantation of P. orientalis at Xishan Mountain, Beijing, China, to determine the diurnal, inter-monthly, seasonal, and inter-annual variation. The effects of T and VWC on the variation of R_S were analyzed by simple models and binary mixed models. The results showed that:1) The diurnal dynamics of R_S were not obvious, with the maximum appearing from 12:00 to 14:00. The curves of the average inter-monthly, seasonal and inter-annual R_S and T showed single peaks, while VWC changes were not obvious. During the measurement periods, R_S ranged from 0.03-7.84 μmol/(m²·s). 2) Q₁₀ (the temperature sensitivity of soil respiration) varied with seasonal changes, with the maximum (3.56) in winter and the minimum (1.31) in spring. The Q₁₀ were 2.01,2.03 and 2.10 for the measurement periods of 2009,0 and 2009-2010, respectively. 3) R_S was significantly correlated with T, but not with VWC. The strength of fit of the simple model was 82.8% for R_S and T, and 20.5% for R_S and VWC. The binary mixed model indicated that the combined effects of T and VWC on R_S were 82.6%.