A flame retardant fabric is directly woven from flame retardant viscose fiber added with inorganic silicon for covering the outside of flammable articles, wherein the flame retardant viscose fiber having denier, strength and flame retardant effect which use silicic acid as the flame retardant, and coating a layer of organic material, melamine flame retardant resin on the surface of silicic acid, and then preparing the flame retardant viscose fiber into an nano-sized particles. The flame retardant fabric has a fineness of 1.11 to 2.78 dtex, and a strength of ≥2.0 cN/dtex, which meets the production requirements of spinning, and does not need to be blended with other high-strength fibers when spinning, and the woven fabric from the flame retardant viscose fiber does not need to be flame retardant, so that the flame retardant fabric has a good flame retardant effect and saves costs through simply the production process.