Abstract: The low order faults lead the oil-water relationship of oil-bearing block reservoirs complicated, especially in those blocks that show poor continuity of single sand spatial distribution and obvious heterogeneity of sand internal structure. The recognition of low order faults plays an important role in finding favorable well location and solving injection contradictions. Based on a single anticlinal structure of Wei 21 Block in Weixing oil field, this article investigates and analyses the relative variation trend of Putaohua top location reflected in the well information of named well line by using the dense well pattern material of Putaohua reservoir group, and achieves the goal of low order fault recognition in this block effectively in conjunction with seismic profiles, so as to provide foundations in designing interspaced well project.