Disclosed are a method of manufacturing a flame-retardant rayon staple fiber, and a flame-retardant rayon staple fiber laminate made from the same staple fiber. The method includes a step of impregnating a flame-retardant staple fiber web with a flame-retardant solution in which a starch and an inorganic powder are mixed and a step of drying the impregnated staple fiber web. When the flame-retardant rayon staple fiber is manufactured by the method, inorganic particles absorbed by the staple fiber do not easily detach, thereby improving flame retardancy of the fiber. When a staple fiber laminate is made from the staple fiber manufactured by the method, the strength of the laminate is improved due to the presence of the starch, and the workability and moldability of the laminate are also improved due to the increased strength.