A preparation method of a skin-care composite facial mask fluid is disclosed. Main raw materials include konjac glucomannan, k-carrageenan, isolated soybean protein, collagen, propolis and vitamin E. The preparation method comprises the preparation of konjac glucomannan sol, the preparation of compound protein solution, the preparation of k-carrageenan solution and the preparation of sucrose fatty acid ester diluent, and compound and blending of all the materials. The konjac glucomannan is a natural biological polymeric membrane material having excellent performance, and has excellent performances such as water sucking property, moisture preservation property, membrane formation property, gelation property, degradability and the like. Through the physical mixing of the konjac glucomannan with the k-carrageenan and the isolated soybean protein, the thermal properties and the mechanical properties of the membrane can be improved; and through formulation, a non-toxic, efficient and good-performance skin-care facial mask fluid is formed. The konjac glucomannan has a unique property of being liquid at a temperature below 10 DEG C and being naturally formed into a membrane at the normal temperature; therefore, the skin-care composite facial mask fluid is applied to face and a membrane can be naturally formed. The skin-care composite facial mask fluid of the invention is colourless and transparent, convenient for use, and non-toxic and safe.