The invention belongs to the field of radar signal processing and discloses a GPU-based video SAR echo simulation parallel implementation method. The method comprises the following steps: copying radar system parameter values from a memory of a CPU to a constant memory of a GPU; transmitting original scene image data in the memory of the CPU to a video memory of the GPU; setting a kernel function and parallelly calculating space coordinates and backscattering coefficients of each point target; setting a kernel function and parallelly calculating space coordinates of a radar platform and instantaneous squint angle between the radar platform and each point target in each azimuth sampling moment; setting a kernel function and carrying out segmentation on all point targets and obtaining echo signals of the point targets in all segmented data; setting a kernel function and obtaining an initial echo signal of the radar at all azimuth moments; and setting a kernel function and obtaining a final echo signal obtained after linear frequency modulation processing as a video SAR echo signal. The method has the advantages of high real-time performance and high efficiency.