Abstract: Huzhuangji oilfield has entered the middle-last development stage with the characteristic of high water containing and high recovery degree, which is difficult for further development. Thus it is important to master the dynamic change of reservoir character to establish fine 3D model of flow unit, which provides the theory for setting up development project. After analyzed the data from coring wells and chose good parameters, we established the standard of differentiated explaining of flow unit and established the differentiated explaining model of flow unit by the methods of cluster analysis and discriminant analysis, then explained the flow unit from coring-free wells. On the basis of above studying, we predicted flow unit among wells by simulation at random, and established 3D predicting model of flow unit.