Distinguishing the decoy and the target is the fundamental problem in countering the Towed Radar Active Decoy (TRAD) jamming. In the course of TRAD jamming, the triangular geometry relationship among the missile, the target and the decoy changes. That brings about the differences of Doppler frequency between decoy and target. Thus it provides the possibility to distinguish the target and decoy in frequency domain. Based on the analysis of the frequency separability in the head-on attack and chase attack scenarios, the L class of Wigner Ville Distribution (LWVD), with the advantages of improving the azimuth resolution and inhibiting the cross terms, was adopted to separate the target and decoy. Then by combining the auxiliary information of echo characteristics and attack scenarios, the identity recognition between the target and the decoy was achieved. The simulation results validated the availability.