Based on the intact soil core-15N isotopic pool dilution approach, this paper studied the gross nitrification rate and net nitrification rate in red soils from three different farmlands and three different forests. The results showed that: the gross nitrification rates of the six fields ranged from N 7.29 μg/(g·d) to 23.50 μg/(g·d). The gross nitrification rates of farmlands were higher than those of forest. In the three farmlands, the gross nitrification rates of the soil with fertilizers were significantly higher than that without fertilizer. Between the three types of forests, the gross nitrification rate of the soil planting Pinus massoniamas increased by 24.8% and 66.9% respectively compared with those of planting Schima superba and Pinus- Schima. The gross nitrification included the net nitrification and the NO3--N consumption. In this experiment, both the gross nitrification and NO3--N consumption rates of the farmland were higher than those of the forest.