[Objective] To study the effect of the wood vinegar on sandy soil microbial biomass and enzyme activity in order to provide the theoretical basis for improving the sandy soil biological quality.[Methods] Compared with the effect of adding tap water on sandy soil, we added different dilution times(200, 150, 100, 50 and 20) of wood vinegar to the soil using pot planting method. Further, the contents of soil dissolved organic carbon, nitrogen and phenol, soil microbial biomass carbon and nitrogen, as well as soil enzyme activities were determined.[Results] Application of wood vinegar to sand soil could significantly decrease soil pH value, increase the contents of readily soil oxidizable carbon, soil dissolved organic carbon, nitrogen and phenol as well as inorganic nitrogen. When the dilution ratio of wood vinegar was greater than 50-fold, the contents of microbial biomass carbon and nitrogen and the activities of β-glucosidase and alkaline phosphatase and dehydrogenase increased with the decrease of dilution ratio of wood vinegar. Compared with the application of 20-fold dilution of wood winegar, the microbial biomass carbon and nitrogen and the activity of β-glucosidase and alkaline phosphatase and dehydrogenase were decreased with the application of 20-fold dilution of wood vinegar. However, the activity of α-glucosidase, leucine aminopeptidase, acid phosphatase and polyphenol oxidase significantly increased with the decrease of dilution ratio of wood vinegar within a certain range(greater than 20-fold dilution) of wood vinegar.[Conclusion] Different concentrations of wood vinegar will affect sandy soil microbial biomass and soil enzyme activity.