Abstract: Through comprehensive analysis of 3rd member Funing formation in western slope of Qintong depression,northern Jiangsu basin,such as petrology,particle size distribution,sedimentary structures and logging facies characteristics,3rd member Funing formation is mainly developed with delta front and shallow lacustrine and semi-deep lacustrine sedimentary facies,and the delta front can be further divided into underwater distributary channel,underwater distributary bay,mouth bar,distal bar and sheet sand,these five micro- facies types.On the basis of this,constrained by analysis results of single well facies and sub-layers division,the plane distribution map of micro-facies of Tai-III and TaiIV sand groups have been drawn.The maps show the sand body of 3rd member Funing formation is mainly from northern delta lobes,with wide distribution and fine lithologic characteristics,Caijiapu-Guzhuang are is centered on underwater distributary channel sediments,while Huazhuang- Yedian- Yuduo-Biancheng area is centered on mouth bar- distal bar- sheeted sand sediments.Therefore,the sedimentary micro-facies of various layers are of some differences.