Abstract: Extracting and interpreting the seismic velocity spectrum data manually is kind of tedious work. The success of developping the "Velocity Spectrum Data Extracting Expert System" makes a great step to realize the automation of this work. This system gather a great deal of human being's experience and put them into the knowledge base. The main inference strategy is through the operation of operation Knowledge-source and Supervisor-source coherently and repeatly, the energy-block can be selected optimumly. It can be used for single Spectrum as well as for Multi-Spectrum. The result of trial applications shows its ability approaches to that of the human experts.