Abstract: An alluvial fan is discovered in the slope zone on the south edge of Xiangcheng depression through special seismic processing such as constrained inversion of XLJ1 seismic line between Well Cl and Well X7. To the north,the fan end uplifts along updip direction and pinches out gradually, and its interval velocity is higher than that of the surroundings, which indicates that sandstone reservoirs might well developed at the fan end area. A relatively large lithologic trap might form due to the fan end uplifting and lithologically pinching out. This possible lithologic trap, near the center of oil source area and with well developed reservoirs, is a target worth furtherprospecting.