In this paper, a novel method is proposed to characterize the operation-waveband angular resolution of the soft X-ray grazing incidence telescope. According to the method, the first is to restore the “geometric image” by removing the aperture diffraction effect from the resolution testing target image measured at visible waveband. The second is to calculate the operation-waveband resolution testing target image by the convolution of “geometric image”, diffraction point spread function and surface scattering point spread function. Finally, the operation-waveband (4.47 nm) angular resolution of 9.72" is calculated according to the operation-waveband resolution testing target image on axis. The method does not need to be performed in vacuum and to place the source away from the solar X-ray grazing incidence telescope, which greatly reduces the testing cost and improves the efficiency for the development of the soft X-ray grazing incidence telescope.