Abstract:A new approach based on theoretical reflectivity seismograms gainning Moho structure was proposed in the paper. The ratio of PmP and Pn’s wave amplitude and adjusts model were used to fit the predicted PmP/Pn curve with measured PmP/Pn curve. Experimental tests indicate that there exists significant difference among the theoretical PmP/Pn curves of Single Layer structure, Gradient Layers structure,layers stacked with high and low velocities structure. SL structure is similar to GLS structure’s PmP/Pn curve in the shape, however, the value of the former is roughly twice that of the latter, and HLVS structure’s PmP/Pn curve appears in concave shape. All shows that this method is sensitive to Moho structure and can be used to identify effectively of Moho structure.