The invention discloses soybean protein / alginate / cellulose fiber and the preparation method thereof. Soybean protein solution, alginat solution and fullbodied cellulose solution are adopted to prepare spinning solution, multilevel coagulation bath is adopted to mold a variety of components to obtain the soybean protein which accounts for 15-60 percent of the total weight of the soybean protein, the alginate and the cellulose, the alginate which accounts for 3-8 percent of the total weight of the soybean protein, the alginate and the cellulose, the cellulose which accounts for 32-82 percent of the total weight of the soybean protein, the alginate and the cellulose. Each level of coagulation bath adopts a non-zinc forming technology, thereby avoiding the protein denaturalization caused by heavy metallic salt and the environment pollution caused by zinc salt, and decreasing the environmental hazard in the fiber production process. Prepared protein and alginic acid in the fiber are mainly distributed at the outer layer of the fiber, the made fiber can fully play the health care performance of the protein and the alginic acid, thus the invention not only has high protein content and good health care performance, and also has good water and salt absorbing performance, and good processing behavior.