Abstract: A laboratory experiment with the soil samples collected from China and Canada was conducted to study the effects of land use type (forestland vs. grassland) and incubation temperature (10  ℃ vs. 15 ℃) on the soil nitrification, nitrogen mineralization, and N₂O and CO₂ emissions under aerobic condition. As compared with forestland soils, grassland soils had higher nitrification rate and N₂O emission, with the highest nitrification rate in China grassland soil. At 10 and 15 ℃, the average net nitrification rate of China grassland soil was 2.10 and 2.86 mg N·kg^-1·d^-1, and the cumulative N₂O emission in 15 incubation days was 10.2 and 15.4 μg N₂ON·kg^-1, respectively. Soil pH was the main factor affecting the nitrification rate and N₂O emission, and there existed significant positive correlations between the soil pH and the nitrification rate and N₂O emission. Forestland soils had higher nitrogen mineralization rate and CO₂ emission than grassland soils, and China forestland soil had the highest nitrogen mineralization rate, with the average net mineralization rate at 10 and 15 ℃ being 3.08 and 2.87 mg N·kg^-1·d^-1, respectively. The CO₂emission was the highest in Canada forestland soil, and the cumulative CO₂ emission in 15 incubation days at 10 and 15 ℃ was 314 and 370 mg CO₂C·kg^-1, respectively. The soil organic carbon and soluble organic carbon contents had significant positive correlations with the soil nitrogen mineralization rate and CO₂ emission, respectively, whereas the increasing soil temperature promoted the nitrification in grassland soils and the N₂O emission from forestland soils and grassland soils. The same pronounced effects of increasing temperature were also found on the CO₂ emission from forestland soils.