The paper deals mainly with the features of phosphatase and the distribution regularities of several enzymes (invertase, alkaline phosphatase, urease and protease) in afforested soils of silting coastal areas of northern Jiangsu. In the fluvo-aquic soil of coastal afforested area, alkaline phosphatase made up 62.6% of the total phosphatase. Suppose the activities of total and alkaline phosphatase are y and x₁ respectively (unit: phenol mg/g), their relation may be discribed by y=-0.04765+1.67426x, r=0.9731. Soil enzyme activities became lower from top to bottom, and they had significant differences in the soil profile. The depth of 60cm for soil sampling could completely meet the need of precision (α=0.05) for the afforested lands and the number of soil samples was 3~4. When the depth was 40cm, the number of soil sample should be at least 4. According to variance analysis, soil enzyme activities had a significant difference in horizontal direction, being far higher in the afforested and farm lands than in the beach land. In the afforested land, the greater the forest age was, the more active the soil enzymes were. Soil enzyme activities in the farm land were similar to those under young forests with intercrops. The same results were also obtained by other statistical methods.