The invention belongs to the technical field of sweeteners, and in particular relates to a stevia glucoside B crystal form G as well as a preparation method, a food composition and the application thereof. The stevia glucoside B crystal form G is measured by a Cu-Ka ray, so that X-ray powder diffraction analysis is obtained; a 2 theta valve expressed in degrees at least has obvious characteristic diffraction peaks at 3.93, 13.45, 16.62, 18.33, 19.90, 23.95 and 28.02. After solid chemical analysis methods such as XRPD, DSC, TGA, DVS and the like are used for carrying out comprehensive characterization on the crystal form G, the crystal form G is found to have the advantages of being high in degree of crystallinity, good in stability and water solubility, low in moisture property and the like, thus being suitable for wider application fields. The preparation method is simple, easy to operate, more in selectivity and good in reproducibility, and can be used for stably obtaining the target crystal form.