Soil organic matter (SOM) in farmland is an important index of assessing soil fertility and soil quality of the farmland and also an integral component of the globe carbon stock.Therefore,dynamic of SOM has an important influence on global climate change.This paper addresses tempo-spatial variation of SOM in Rugao City,Jiangsu Province,an area typical of the Yangtze River Delta Region.In space,loamy Stagnic Anthrosols (Baipu) and clayey Aquic Cambosols (Changqingsha) distributed in the eastern and southern parts of the area,respectively,were high in SOM content;sandy Ustic Cambosols (Guoyuan),and sandy Aqutic Cambosols (Motou) distributed in the mid-western part were low in SOM,and loamy Aquatic Cambosols (Banjing,Dongchen,and etc.) distributed in the northern and southern parts were medium in SOM.In time,SOM showed a risng trend in the past 20 years (1982-2002).From 1982 to 1997,the rising trend appeared to be a steep curve in the mid-western parts,but a flat slope in the eastern and southern parts.From 1997 to 2002,the trend,however,leveled off in the mid-western part and soared up in the eastern and southern parts.Finally,the paper further discusses and analyzes factors influencing the tempo-spatial variation of SOM and puts forward suggestions for soil management and utilization in the future.