To solve the problem that the traditional PRI sorting algorithm has difficulty in effectively identifying the key radar signals with complex PRI changes, a method of fast target recognition of key radar signals based on the characteristics of crystal oscillation is proposed. This method avoids the sorting procedures of the conventional PRI sorting algorithms, and uses the correlation between the PRIs to sort the pulse signal. This method can identify multiple targets simultaneously. According to the principle of PRI generation, whether the PRI change is complex or not has little effect on the recognition result.Through simulations and comparison, it is proved that the proposed algorithm can rapidly identify the pulse sequence of the key radar signal, and get a better recognition result of the radar signal with complex PRI changes.