Abstract: In recent years, ground penetrating radar (GPR) has been widely used as a technical means to understand the characteristics of subsurface geological deposition. However, there has not been any ground penetrating radar to recognize the internal configuration of the dam. The aim of this study is to form a composite dam with a point bar stack. Firstly, the highest resolution frequency of GPR is selected, and then the data are taken in the study area. And eliminate the influence of various factors on data volume. On the basis of the previous work, the location, the formation mechanism and the spatial distribution of the composite dam are determined by measuring the location of the point dam overlap and the dip angle, inclination and thickness of the lateral accretion.