The invention discloses a flame-retardant aid for a natural fiber sofa fabric. The flame-retardant aid contains the following components in percentage by weight: 20%-25% of an acrylic emulsion, 12%-26% of ammonium polyphosphate, 8%-12% of melamine, 18%-25% of annular phosphate, 0.5%-2% of polyoxyethylene ether and the balance of water. The flame-retardant aid is researched for sofas produced from natural fibers (cotton, flax and the like), and good flame retardance can be realized only by coating the surfaces of the natural fibers with 0.5mm-2mm or a small amount of the flame-retardant aid; the flame-retardant aid is simple in constitution, low in cost and high in durability; and when the flame-retardant aid is used in a family, the fire in the family can be reduced, the safety of the family can be guaranteed, the softness, air permeability and lightness of the fabric can be preserved, the peculiar feel is not generated during the direct contact between a human body and the sofa fabric, and the use of the sofa fabric is not influenced.