Soil nitrogen mineralization is a key component of the nitrogen biogeochemical cycle, which indicates the potential of the soil nitrogen supply, and its changing process will impact the productivity of forest ecosystems. In this study, soil samples were collected from the typical plots of primitive Korean pine forests and clear cutting-formed the secondary broad-leaved forests in the Lesser Khingan Mountain,Northern China; then they were cultivated aerobically under indoor conditions at different culture temperatures (4℃, 12℃, 20℃, 28℃, and 36℃) and humidity (20%, 40%, 60%, 80%, and 100% saturated water holding capacity; WHC). Soil nitrogen transformation rates were compared between primitive Korean pine forest and the secondary broad-leaved forest. The results showed that the organic matter, total carbon, total nitrogen, nitrate nitrogen, carbon-to-nitrogen ratio, total phosphorus, available phosphorus, available potassium, and pH in the surface soil (0-20 cm) were significantly increased (P < 0.05) and ammonium nitrogen significantly decreased (P < 0.05) in the secondary broad-leaved forest compared to the primitive Korean pine forest. An analyses of variance showed that net mineralization rate and net nitrification rate of the surface soils were significantly lower in the primitive Korean pine forest than the secondary broad-leaved forest; however, net ammonification rates showed the opposite trend when it was compared between the two forest types. Soil nitrogen transformation rates were significantly affected by the temperature and humidity (P < 0.001). There were significant differences in responses of net mineralization rate to changes in temperature and humidity between the primitive Korean pine forest and the secondary broad-leaved forest, the optimum temperature and humidity were 28℃-36℃ and 60% WHC for the soils of both forests. The temperature sensitivity index of soil nitrogen mineralization (Q₁₀ value) in the primitive Korean pine forest was significantly higher than that of the secondary broad-leaved forest (P < 0.05). The Q₁₀ value was negatively correlated with the matrix quality index (A) and soil organic matter(P < 0.01).