Effect of long-term rice straw incorporation on soil enzyme activities in paddy soil under rice-wheat rotation in the Taihu Lake Region of China was investigated. Seven enzymes closely related to soil biological activities and C, N, P and S cycles, i.e., Fluorescein diacetate (FDA), acid phosphatase, alkaline phosphatase, arylsulfatase, β-glucosidase, urease and dehydrogenase, were selected. Results showed that compared with CK, the treatment with no fertilizer, treatments with chemical fertilizers or rice straw showed significantly enhanced enzyme activities. In terms of sensitivities to rice straw incorporation or chemical fertilizer, the enzymes was in the order of β-glucosidase > dehydrogenase, urease > FDA, alkaline phosphatase > arylsulfatase > acid phosphatase, while in terms of enzyme activity the treatments followed the order of NPKS2(NPK+rice straw 4500 kg/hm²) > NPKS1(NPK+rice straw 2250 kg/hm²) > NPK (N 120 kg/hm²+P 75 kg/hm²+K 150 kg/hm²) > CK.