Abstract: Soil enzymes play an essential role in catalyzing reactions necessary for the decomposition of organic matter and nutrient cycling in ecosystems, involving a range of plants, microorganisms, animals and their debris. In this paper, black soil samples at the depth of 0-20 cm were collected from the Hailun Agricultural Ecology Station of Chinese Academy of Sciences to study the effects of different land uses and fertilization systems on urease, invertase, phosphatase, and catalase activities, total carbon (TC), nitrogen (TN), alkaline hydrolytic nitrogen, available P and available K. The results showed that soil enzymes activity, TC, TN alkaline hydrolytic nitrogen, available P and available K in both clover land and fallow land significantly increased compared with bald land, in which urease activity increased by 24.5% and 25.0%, invertase activity 18.4% and 18.9%, phosphatase activity 54.6% and 50.4% and catalase activity 8.52% and 59.3%, TC and TN increased by 13.8%, 13.0% and 36.8%, 33.7%, respectively. However, there was no significant difference between clover land and fallow land. There was a significant difference of soil enzymes activities, TC, TN and available nutrients contents among the treatments under different fertilization systems, which followed same order: nitrogen, phosphorus and potassium fertilizers plus organic manure (NPKOM) nitrogen, phosphorus and potassium fertilizers plus straw (NPKST) nitrogen, phosphorus and potassium fertilizers combination (NPK) control (CK). Fertilization, especially organic manure application, could significantly increased soil enzymes activities, TC, TN and available nutrients contents. These results suggested that black soil fertility and quality could be improved either by natural or artificial reclamation or by fertilization.