The invention relates to a konjac glucomannan synthetic casing and a preparation method thereof. The preparation method of the konjac glucomannan synthetic casing comprises steps of preparing a porouskonjac glucomannan film, performing two-stage homogenization treatment, preparing a cylindrical film, and preparing the konjac glucomannan synthetic casing. Konjac glucomannan taken as the main ingredient has various characteristics of hydrophilicity, thickened property, stability and the like, and preparation of high-quality porous nano-films from natural plant polysaccharides as raw materials becomes a hotspot in recent years. The porous konjac glucomannan nano-film, obtained by means of the specific gel property of the konjac glucomannan and the application of the electric field technology, has great application potential. The konjac glucomannan synthetic casing used for replacing the conventional casing has good water binding capacity and can protect flavor of sausages, is free of off-flavor and can guarantee original taste of the sausages; production is easy to operate, and unexpected effects such as continuous production and the like can be realized.