In recent years, orthogonal frequency-division multiplexing (OFDM) synthetic aperture radar (SAR) imaging has been introduced and an inter-range-cell interference (IRCI) free OFDM SAR has also been proposed. In this paper, we use this idea and propose an IRCI free cyclic prefix (CP)-based OFDM inverse synthetic aperture radar (ISAR) imaging which provides a high range resolution ISAR image. However, in order to use this algorithm, the motion parameters of target should be determined. Thus, before applying the algorithm, the motion parameters are estimated through proposing an iterative entropy-based method (IEBM). The proposed imaging algorithm and the IEBM are verified by simulations for CP-based OFDM ISAR.