Mahuangshan western block includes complex fault zone in western and stable region of formation in eastern, the main traps of the former are the structural traps and the main traps of the latter are the structural-lithological traps, but the sand body of J1y formation is thin and changes quickly in lateral, and the quality of two-dimensional seismic data is poor, thus reservoir prediction of J1y formation is very difficult. Analyzing seismic reflection structure of the known well with seismic reflection structure principle of reservoir and two-dimensional model in seismic stratigraphy, and the reflection mode of channel sands for J1y formation is summarized.