Abstract: A spherical bent crystal was developed based on Bragg diffraction to diagnose laser plasma X-ray. Spatial resolution, spectral resolution and radiation collected by solid angle were increased by using the spherically bent crystal. The spherically bent quartz crystal and X-ray imaging plate were adopted as X-ray analyzer and imaging device respectively. The imaging experiment was carried out with an X-ray diffractometer using Cr-target. The experimental results show that the monochromatic image of two-wire with a space of 0.2mm is obtained, the spectrograph of the spherically bent crystal offers good spectral resolution and signal-to-noise, and the calculated wavelength resolution reaches 1000 in 0.2 nm~0.4 nm. The spherically bent crystal is suitable for diagnosing soft X-ray spectroscopy, and the focusing intensity for spherically bent crystal is an order of magnitude higher than plane crystal at the same condition.