Abstract: When an inverse synthetic radar(ISAR) imaging the targets on sea surface,sea clutter may decrease the imaging performance.In this paper,we analyze the clutter probability distribution function,and examine the temporal and spatial correlation properties of the clutter.A sea-clutter simulation method is presented,and an algorithm to reject the sea clutter in ISAR signals is proposed.In the simulation method,the K-distribution coherent clutter is generated by spherically invariant random process,followed by two linear transformations,the two dimensional clutter with the given temporal and spatial correlation is obtained.In order to improve the ISAR images quality in presence of sea clutter,we set an appropriate threshold in the ISAR images through the constant false alarm rate processing,hence the scatter signals are retained and sea clutter is rejected.Finally the simulation results demonstrate the effectiveness of the algorithm.