Abstract: The present status of automatic processing of seismic data by the appli-cation of sign-bit correlation and the theory of fuzzy mathematics is revie-wed,with particular emphasis on the enunciation of the theory and practice of velocity spectrum of sign-bit correlation,automatic pickup and automatic amplitude staking of velocity as well as sign-bit stacking.From experiment,it has been proved that in the light of the character of the sign-bit corre-lation spectrum and with the application of the basic principles of fuzzy mathematics,one can readily and very approximately simulate the process of interpreting velocity spectrum so as to extract velocity parameters automatically for use in stacking and other processing operations.Moreover,the output of velocity section may show clearly velocity variations both vertically and laterally.The successful processing of sign-bit correlation has given promise to raise the accuracy and resolution of seismic survey through full sign-bit acquisition and processing with high coverage and high sampling rate.It also paves he way for repeating automatic processing on a more general scale in order to make more comprehensive interpretation.