Ocean wave spectrum and surface currents can be determined from a series of spatial wave images recorded by X-band marine radar.In the absence of surface current

the three-dimensional spectral energy resulted from the series of images will be confined to a trajectory defined by the still water dispersion relationship.The presence of a surface current will make the three-dimensional spectral energy show a corresponding Doppler shift from which the current velocity can be inferred using the least squares method and then the directional wave spectrum can be also obtained.On the basis of conventional wave spectrum and directional function

the paper emulates a series of X-band radar images considering shadow modulation and simulates numerically the three-dimensional spectrum both with and without ocean surface current

calculates the current velocity by virtue of the Doppler shift

and obtains the two-dimensional image spectrum.Finally the paper analyzes the ocean data measured in a fixed staring direction by an X-band radar in McMaster University and obtains the one-dimensional image spectrum.