A simulated rainfall experiment was conducted to detect the response of forest soil respiration to precipitation change in the Jiufeng National Forest Park, Beijing City. Platycladus orientalis was chosen as the representative tree. Soil respiration rate in different stand ages was measured in conditions of 5, 10, 20 and 50 mm rainfall depths and consecutive identical frequency. Results indicated that there was significant variation(p<0.05) in the impact of stand age on soil respiration rate of Platycladus orientalis, and the soil respiration of 30-years-old Platycladus orientalis generally exceed that of 10-years-old. Compared with control group, 5,10 and 20 mm rainfall tests all had auxo-action effects on soil respiration of 30-years-old Platycladus orientalis and 50 mm rainfall and consecutive identical frequency were suppressive on 30-years-old Platycladus orientalis' soil respiration. 10-years-old Platycladus orientalis needed less water than 30-years-old Platycladus orientalis and hence, only 5 mm rainfall could promote soil respiration rate, while the others presented suppressive effect.