Abstract: Focusing on the cultivated land and forest land in Hailun City of Heilongjiang Province, the paper analyzes the effects of land use types, soil depth and some geochemical characteristics on the activity of soil sucrase, urease and peroxidase. The results show that sucrase is significantly affected by soil depth, with the sucrase activity in surface layer obviously higher than that in deep layer, but not by land use types; while urease is less affected by soil depth than by land use types. Therefore soybean planting can drastically increase soil urease activity. Besides, urease activity is also affected by soil clay content. The peroxidase activity is mainly controlled by soil organic carbon (SOC) content, with less affection by soil depth, but the peroxidase activity in deep soil of forestland is significantly higher than that of cultivated land.