Abstract: To recognize the earthquake precursor phenomenon's characteristics, the frequency cha racteri zation of earthquake precursor is an important approach. The research on the f requency cha racteri zation of precursors can be helpful to recognize the precursor signals and to know precursor mechanism. This resea rchcan promote the improv ement and perfection of its observation system. By using the daily mean values of geoelectric resistivity of Baodi station from 1970 to 1995, according to the precursor pheno menabefo re Tang shanear thquakein 1976, we advanced a new method by using the binary wavelet transformation to so lv e the precursor da ta sequence into a series of successive frequency bands. Then to recognize and ex tract the anomaly signals, which can greatly improve reliability of precursor recognition and pro mote the study of precursor phenomena.

Key words: Wavelet transformation, Earthquake precursor, Frequency