The Extreme Ultraviolet Telescope(EUT)’s operational wavelength band is smaller nearly two levels than that of the visible light and its in-band diffraction limit is very low

so it is very difficulty to measure a angular resolution in extreme ultraviolet band. In this paper a new evaluation method using ZYGO interferometer to test the figure error and alignment error of the EUT in visible light is introduced. Then

the Zernike coefficients independent of the operational wavelength are brought into the optical design software

so that the point spread function and diffraction encircled energy in operational wavelengths can be obtained by the optical software. Finally

the angular resolution of the EUT in extreme ultraviolet band is calculated by the relative parameters.Experimental results show that the evaluation method has the advantage of high speed and efficiency for an imaging apparatus in extreme ultraviolet band.