In order to diagnose the distribution, stability, dimensions and plasma uniformity of pellet implosion in the inertial confinement fusion (ICF), an X-ray backlight imaging system based on spherically bent crystal has been set up using the X-ray Bragg diffraction theory. The primary component of the imaging system is the spherically bent α-quartz crystal which has characteristics of stability, complete structure, high reflectivity and resolution. The crystal dimension is 65 mm×20 mm and the curvature radius is 143.3 mm. Monochromatic X-ray backlight imaging experiment using the imaging system has been carried out. In the experiment, the object is a 3×3 array square stainless steel grid. It obtains two-dimensional monochromatic X-ray backlight image of chrome in imaging plane. The X-ray backlight imaging system based on spherically bent crystal provides an approximate 83.3 μm spatial resolution and a 9.6 mm×28.7 mm field of views. It is demonstrated that this backlight imaging system could be used for monochromatic X-ray backlighting imaging diagnosis.