Abstract: Soil quality comprehensively reflects soil properties and is the most sensitive indicator mirroring dynamic changes of soil condition under the influences of human activities. It is very important for the prevention of soil degradation and the sustainable utilization of soil resources to research the changes of soil quality under the influences of the human activities. The Sanjiang Plain has been built into an important foodstuff base since large area reclamation in 1949. But due to lacking of environmental protection awareness and blindly pursuing economic benefit in the earlier reclamation processes, the soil environment of this area degrades, which will influence the sustainable development of agriculture. This paper establishes soil quality change evaluation model to calculate the soil quality matrixes of the top soils(cultivated layer soil)of the main cultivated soils in the Sanjiang Plain. The Changjing trend of soil quality after large area redamation in the Sanjiang Plain are quantitatively evaluated through analyzing the changes of soil quality indexes of the top soils of the main cultivated soils. Results show the quality indexes of the top soils of the main cultivated soils decrease after large area reclamation. Moreover, with the increment of the cultivation years the indexes decrease more. In the end, the forming reasons of this changing trends is simply discussed.