The invention relates to the technical field of fingerstalls, in particular to a fingerstall for correcting allotriophagia and promoting fingernail growth and a preparation method thereof, which utilize the characteristic that children who suck fingers or bite fingernails like to bite the fingerstall, adopt a fingerstall form, and respectively smear different liquid medicines on the inner layer and the outer layer of the fingerstall to play different effects. The outer-layer medicine adopts andrographolide, gentiopicroside and denatonium benzoate as bitterness agents, the outer-layer medicine is insoluble in water, the fingerstall is not afraid of washing after being worn, and the concave points of the fingerstall can store part of the outer-layer medicine, so that the bitterness and the antibacterial performance of the finger stall can be kept for a long time; allantoin and vitamin B in the inner-layer medicine support cell metabolism and promote the growth of damaged nails, when children gnaw the nail, nutrient particles in the inner-layer medicine are crushed when the children gnaw the nail, nutrient components are released, the nails are further repaired, and fungus growth is inhibited; the material of the fingerstall has certain elasticity, is fit, breathable, washable, wear-resistant and not easy to damage, and has important significance for quitting the allotriophagia symptoms such as gnawing hands, gnawing nails, biting toys and the like.