Abstract: Aiming at the problem of radar signal extraction of interleaved pulse sequences intercepted by reconnaissance receiver, according to the description technique of pulse recurrence interval(PRI), a pulse extraction algorithm is proposed based on the searching of PRI Pulse Sequence Subpattern cycle. In this algorithm, the idea of searching adjacent pulses intervals in traditional PRI searching algorithm is replaced by that of searching the PRI Pulse Sequence Subpattern cycle. A two-dimensional extraction function consisting of time of arrival and paracycle of PRI pulse sequence subpattern is constructed to store the number of matching pulses which conform to a certain assumed PRI Pulse Sequence Subpattern(PSS) cycle during the searching process. Then the PRI Pulse Sequence Subpattern cycle is determined according to the maximum value of the function, thus the equivalent pulses can be extracted, realizing the signal extraction of complex type of PRI radar. The validity of this method has been verified by simulation experiments.