Abstract: Taking the third member of dongying formation in the second block of Shengtuo oilfield as research object, the paper deals with reservoir plane heterogeneity in different development stages based on heterogeneous synthetic index and its plane contour map. The heterogeneous characteristics in different development stage are analysed, and the variation regularities are obtained. Besides, the relationship between the reservoir plane heterogeneity and the distribution of remaining oil is also discussed. The results prove that the degree of reservoir plane heterogeneity varies with the process of the further waterflood development. In the earlier stage the degree of reservoir heterogeneity is mainly middle to relatively strong; in the middle stage it is stronger; and in the later stage it is mainly relatively strong. According to statistic analysis, about 75 percent remaining oil distributed in the reservoir with relatively stronger heterogeneity.