Abstract: Wide-band phased array radar is the primary focus of electronic warfare reconnaissance, and prior extraction of such radarsignals in the interleaved pulse data intercepted by the receiver has important military significance. Aiming at full pulse data intercepted by the receiver, a method of prior extraction of wide-band phased array radar signals is proposed in this paper. Wide-band phased array radar works by means of electronic scanning, so in the same work mode its pulse amplitude remain unchanged. Utilizing such feature, this method introduces a dichotomizing reasoning algorithm in bioinformatics, together with the pulse width characteristic of wide-band signals. Firstly, reorder the full pulse data filtrated by pulse width threshold according to pulse amplitude; then, test the discontinuity points of pulse amplitude by employing the dichotomizing reasoning algorithm, dividing the pulse sequences into segments with the same pulse amplitude; lastly, conduct pulse number threshold filtering on every segment, realizing the extraction of wide-band phased array radar signals. The validity of this method has been verified by simulation experiments.