A time-resolved multispectral X-ray imaging approach with new version of multi-channel Kirkpatrick-Baez (KB) microscope is developed for laser plasma diagnostics at the kilojoule-class Shenguang-II laser facility (SG-II). The microscope uses a total external reflection mirror in the sagittal direction and an array of multilayer mirrors in the tangential direction to obtain multiple individual high-resolution, highthroughput, and quasi-monochromatic X-ray images. The time evolution of the imploded target in multiple X-ray energy bands can be acquired when coupled with an X-ray streak camera. The experimental result of the time-resolved 2.5 and 3.0 keV dual-spectral self-emission imaging of the undoped CH shell target on SG-II is given.