In order to break the limitation of the spherical mirror's surface shape on the spatial resolution of the traditional Kirkpatrick-Baez (KB) microscope, an optical design method for the aspherical KB microscopy imaging system was established. Elliptical cylindrical mirrors were used instead of spherical mirrors, and the mathematical expressions of the mirror parameters were calculated through geometric relationships. Combining the quantitative analysis of the influence of main optical structure parameters on spatial resolution, a set of optical structure parameters of aspherical KB microscopes suitable for current high-power laser devices in China were proposed, and the imaging experiment was carried out in the lab. The experiment shows that in the central field of view, the spatial resolution is better than 2 μm, and in the field of view of 200 μm, the spatial resolution is better than 5 μm, and the geometrical solid angle can reach 1.3×10^-6 sr. Aspherical KB microscope effectively improves the resolution of the central field of view of the KB microscope, which meets the needs of high-resolution diagnosis during the deceleration stage of implosion targets.