Abstract: Aiming at meeting the engineering demands for mass high resolution ISAR images by template-based target recognition, an efficient signal level ISAR simulation approach is proposed based on parallel computation technology of electromagnetism scattering. The electromagnetism scattering from target is calculated by the hybrid physical optics (PO) and equivalent edge current (EEC) method, which is accelerated with parallel computing technology based on OpenMP. Stepped frequency wave form (SWF) is chosen as the radar radiation wave form. With the data of electromagnetism scattering from target the wide-band echo is generated in stepped frequency wave form. Finally, the ISAR image is obtained using the Range-Doppler algorithm (RDA), and the difference from the ISAR image of scattered point model is analysed. The signal level ISAR imaging fast simulation is implemented in this approach, which is of important significance on the design and verification of ISAR system, the ISAR image interpretation and target recognition and the image processing.