Abstract: The dynamics of soil NH4+-N and NO3--N in a pine forest of Dinghushan were investigated using ion exchange resin bag method. Soil NH4+-N and NO3--N both exhibited significantly seasonal variations, with the highest in spring and the lowest in summer. In the soil at 0～10 cm and at 10～20 cm depth, the mean values of soil NO3-N were 1. 722 and 1.429 μg·d-1· g-1 dry resin, respectively. However, in the soil at 0～10 cm and at 10～20 cm depth, the mean values of soil NH4+-N were 19.137 and 14.696 μg·d-1· g-1 dry resin, respectively. NO3--N was positively correlated with NH4+-N at both soil depths for most seasons (P<0.05) ,indicating the importance of ammonium supply in regulating nitrification rates.