The diagnostic demand of hot-spot intensity distribution in laser inertial confinement fusion experiment has motivated quantitative measurement experiment to give the response efficiency of grazing incidence system to improve the accuracy of the diagnosis. In our study, a full-aperture intensity response measurement method is proposed, which is based on pinhole-scanning field of view (FOV) to obtain the response efficiency of grazing incidence system. The method is highly repeatable and enables response efficiency measurements over the full FOV with acceptable accuracy. A silicon positive-intrinsic-negative detector with an energy response range of 1.5 to 30 keV is used to directly detect the input and output spectrum. The response efficiency of a single-channel aspheric Kirkpatrick–Baez (KB) microscope coated with W/Si is obtained under the FOV of ±150 μm. The response efficiency of center FOV of the KB system is measured to be 2.52E-7 sr. The value is promising, as it shows a 6.6% maximum deviation from the theoretical value at center FOV, with a global uncertainty of 7.4%.