Abstract: There are many micro-fractures in the CA Oilfield in Gaoyou Sag,the North Jiangsu Basin.The aperture and extension length of these micro-fractures are too small to identify easily.The methods and means being used to study are limited.Based on the acoustic logging curve,the microinverse,the micronormal,the 6 m electric resistance curve and the resistivity curve in flushing zone,the 3D mathematical model about the distribution of the micro-fractures in this area can be established by using the method of artificial neural network.In this paper,the micro-fracture parameters were predicted by this way.The predict result was verified by the dynamic data analysis.It is reliable to predict the distribution of micro-fractures by using the mathod of artificial neural network.