Since the topograpthy of coastal regions is complex, which has a clutter model much different from the traditional statistic model, so it becomes a difficulty to simulate clutter of coastal regions accurately and rapidly. First, the method for calculating relevant parameters of scattering cells based on digital elevation model, airborne radar parameters and the location of plane, is described. The steps for simulating the clutter power spectrum by these parameters are presented, i. e. , judging each scattering cell belong to which range-Doppler cell, accumulating the power of scattering cells in the same range-Doppler cell, and implementing heterogeneous clutter power spectrum simulation. Because of the huge calculation amount in the simulation, the paper also provides a method to accelerate clutter simulation depending on compute unified device architecture in GPU. The simulation result of the radar clutter power in coastal regions is consistent with the real terrain environment, which is accurate and effective. As for the simulation speed, this method has significant improvement compared with the traditional methods, which is practical in engineering.