Abstract: During the process of reservoir inversion, a logging trace which can distinguish the reservoir from adjacent rock and have a good relationship with seismic response should be confirmed to rebuild the reservoir and build geological model so that we can make reservoir prediction, and this curve is called characteristic curve. In this article, the author analyzes the reservoir characteristic and the well logging curve feature of Pinghu Field and suggests using the gamma ray curve as the characteristic curve. At the same time, the author depicts the theory of choosing characteristic curve in detail and the process of reservoir rebuilt by characteristic curve. At the end of the article, the author clarifies the validity and applicability of this method by the actual application effect.