High dynamic range and large format technique of micro-chanunel plate (MCP), gated framing camera is developed to diagnose high-power laser-plasma X-ray emission spectra. The single frame format is 13 mm×36 mm, and exposure time is adjustable from 0.5 ns to 5 ns. Its spectral response in 1.0—10 keV is more flat than that of X-ray charge-coupled device (CCD), and there exists no energetic enhancement effect. Performance evaluation has been conducted on high power laser devices, and the results show that the system has a high signal-to-noise ratio and the dynamic range is greater than 3 × 103. The system has been applied successfully to inertial confinement fusion (ICF) physics experiment.