Abstract: This article discusses in detail the character of Inverse Synthetic Aperture Radar (ISAR) multi-target imaging techniques and time-frequency algorithms. Based on the model of rigidity multi-target of multiple ballistic missiles, time-frequency analysis technology is proposed to simulate imaging of multiple targets. Also, Range-Doppler (RD) and three ISAR time-frequency algorithms for multi-targets imaging are compared. The result is given to prove the feasibility of ISAR imaging and recognition of multiple targets.