In order to diagnose the inner distribution and movement process of pellet implosion target plasma for laser-driven Inertial Confinement Fusion (ICF) facility, an energy spectrum imaging system based on spherically bent crystal was built. The core element of the system was a spherically bent quartz crystal (1011) with bending radius of 200 mm, of which the lattice structure enabled reflection and the bent surface made focus. The energy spectrum imaging system was performed to first conduct X-ray energy spectrum imaging on SG Ⅲ prototype laser equipment at the Chinese Academy of Engineering Physics (CAEP). Clear X-ray energy spectrum of the high Z element Au plasma was obtained on IP imaging plate. The analysis on the energy spectrum information shows that the energy resolution ratio gained from spherically bent quartz crystal is approximately 1 380, and the error is 39% compared with the theory value of energy spectrum resolution model. The result shows that spherically bent quartz crystal has good energy spectrum resolution capacity.