One of the hot issues of the current research on agricultural land quality is how to employ remote sensing image processing technique to monitor the temporal-spatial changes of agricultural land quality dynamically. The paper elaborates on grid-pixel based vegetation index in light of MODIS image and agricultural land grading data of agricultural land in Jiangsu Province, since vegetation index is an efficient characterization to measure natural quality of regional agricultural land; it, taking Yixing as research region, also analyzes the correlativity between vegetation index from remote sensing image and natural quality index of agricultural land by combining GIS spatial analysis and statistics principles. The Paper builds regression model, with which it takes a sample from agricultural land in Wuxi for test; the result shows that the model has a good fitting degree and it is feasible to making NDVI-based dynamical monitoring on the temporal-spatial changes of agricultural land quality.