Abstract:【Objective】 To understand the effects of land use type change on soil N cycle and eco-environment, this study aimed to elucidate the gross N transformation rates in soils under different land use types. 【Method】 A laboratory incubation experiment was conducted using a 15N labeled technique and the numerical FLUAZ model to study the difference of gross N transformation rates among soils under different land use types such as wetland, dryland, vegetable land, and forest land in the Caohai nature reserve located in the Yunnan-Guizhou Plateau. 【Result】 The results showed that land use type significantly affected gross N transformation rates in the soils. Wetland soil had the highest rates of gross N mineralization (11.95 mg·kg-1·d-1) and immobilization (6.13 mg·kg-1·d-1) while the forest soil had the lowest gross N mineralization rate (2.39 mg·kg-1·d-1), but the gross N immobilization rate (2.09 mg·kg-1·d-1) was comparable to that of dryland soil and vegetable soil (2.29 and 1.52 mg·kg-1·d-1, respectively). The gross nitrification rate of forest soil (0.77 mg·kg-1·d-1) was significantly lower than that of wetland soil, dryland soil, and vegetable soil(2.68, 6.33 and 5.39 mg·kg-1·d-1, respectively). The ratios of gross nitrification to NH4+ immobilization and gross N mineralization to the immobilization of dryland soil and vegetable soil were both >1, whereas the ratio of gross nitrification to NH4+ immobilization rate was <1 in wetland soil and forest soil, and the ratio of gross N mineralization to the immobilization rate was close to 1 in forest soil. The gross N mineralization rate was significantly positively correlated with soil organic carbon (SOC), total nitrogen (TN), C/N ratio, and soil pH, and significantly negatively correlated with silt content. Also, the gross N immobilization rate and ammonium immobilization rate were significantly positively correlated with SOC, TN, water-soluble organic C(SOCw), and soil pH, and significantly negatively correlated with silt content. The gross nitrification rate was significantly negatively correlated with SOCw and clay content and significantly positively correlated with sand content. 【Conclusion】 The results indicate that in comparison with the wetland soil, dryland soil, and vegetable soil, the mineralization and immobilization processes in forest soil were more tightly coupled, thereby decreasing the occurrence of nitrification and subsequent NO3- loss to the environment. The results of this study can provide a scientific basis for the rational layout of land use and the evaluation of the environmental effects of ecological restoration projects within the Caohai Nature Reserve.