ObjectiveForest fire, as the primary natural and human-induced disturbance in subtropical forests, seriously affects the soil biochemical cycle. We aimed to clarify the response of soil extracellular enzyme activities to the restoration process following forest fire disturbance.MethodsWe investigated the soils of subtropical secondary forests at different stages of recovery following forest fire disturbances. Subtropical forest soils at seven stages of restoration were analyzed using a spatial substitution time series approach. The forests were categorized into three age groups, including old forests (60—70 years), middle-aged forests (30—40 years), and young forests (< 20 years). We aimed to reveal the succession patterns of extracellular enzyme activities and their stoichiometric characteristics following forest fire disturbances by measuring invertase activities related to soil carbon (C), nitrogen (N), and phosphorus (P) in subtropical forest soils.ResultsThe activities of soil cellulose hydrolase (CBH) and β-N-acetylglucosaminidase (NAG) increased significantly with forest stand age, but the activities of other extracellular enzymes did not increase significantly with stand age. Correlation analysis and redundancy analysis showed that soil C and N contents were the key factors affecting the change of soil extracellular enzyme activities. In addition, the ratios of soil extracellular enzyme C, N and P were 1∶0.94∶1.53, 1∶1.02∶1.63 and 1∶0.99∶1.47 in young, middle and old forests, respectively, indicating that soil microorganisms in subtropical forest was limited by P, but such P-limitation was improved gradually with forest stand age following forest fire disturbance.ConclusionThe extracellular enzyme activities related to soil N transformation increased with forest stand age following forest fire disturbances in subtropical forest soils. The stoichiometric characteristics of soil extracellular enzyme gradually tended to be stable, indicating that soil health was progressively improved during the restoration process following forest fire disturbance in subtropical forests.