In this study, we propose a spherical crystal based on X-ray fluorescence imaging system with high spectral resolution and full field of view (FOV). Further, the spatial resolution, FOV, spectral bandwidth, and photon collection efficiency are analyzed. Next, we present the design of the fluorescence imaging system for the K_α emission of a metal (V-Zn) with median atomic number according to the theoretical analysis, and the analytic theory and a custom-written Monte Carlo ray-tracing code are used in calculation and simulation. Our theoretical analysis and simulation demonstrate that the X-ray fluorescence imaging technique exhibits a high spatial resolution (<80 μm), large FOV (>6.5 mm), and high spectral resolution (<16.5 eV@4.6-9 keV).