Changshu County in Jiangsu Province was chosen as a typical region in investigating variation of soil fertility between 2000 and 2006 in the Yangtze River Delta.Two sets of soil chemical property data were compared and the in tegrated soil fertility index(IFI) method was also used to evaluate soil fertility as a whole.Results show that soil organic matter(SOM),tolal nitrogen(TN),total phosphorus(TP),total potassium(TK),CEC,available phosphorus(AP),available potassium(AK) all increased in the fields after 6 years of cultivation,while pH decreased.Among all the changes,TN,TK and AP in creased most significantly.In this study,the increment of TN,TK and AP varied in the range of 0~4 g kg^-1,1~2 g kg^-1 and 0~5 mg kg^-1,respectively.The IFIs obtained in soil surveys of both 2006 and 2000 were mainly scattered in the 2 top grades,excellent and good,and the in tegrated soil fertility in 2006 displayed an increasing trend as compared to that in 2000,indicating that the soil fertility was improved during the cultivation.