At the present time, AVO responses classification is the basic and most efficient method to predict reservoir. However, there are still many problems in its applications. The number of successful cases is almost equal to number of unsuccessful cases. The main reason is that there are many factors which affect AVO responses, such as lithology, physical property, fluid property, lithogenesis, and burial depth, etc. Considering these factors, it is necessary to analyze specific AVO response for a particular area on the basis of classical AVO classification. Based on the physical property parameters surveyed in the actual drilled wells of western Africa offshore, several possible petrophysical models are designed, and some forward AVO modeling on different fluid substitutions at different depth interval is performed. It is summarized that the characteristics of AVO response changes at different depths on different fluid substitutions. The applications of AVO classification in this area are also improved and some empirically depth ranges in which the AVO classification could be effectively applied to is provided.