The invention relates to coagulating bath for cellulose solution spinning forming and a method for preparing cellulose fibers by the coagulating bath. The coagulating bath, which is particularly used for cellulose solution spinning forming on the basis of alkali/urea/water system solvent methods, can be of used in one stage or multiple stages; the coagulating bath used in each stage is aqueous solution containing phosphoric acid and/phosphate. The coagulating bath is economic, environmentally friendly and recoverable; the cellulose fibers prepared by the coagulating bath are thorough in coagulation without doubling, and are soft and glossy, the fiber interfaces of the cellulose fibers prepared by the coagulating bath are circular and have smooth surfaces, and the intensity of the cellulose fibers is higher than 2.7cN/dtex; the used coagulating bath solution can be used as liquid phosphate fertilizer or recovered and prepared into solid phosphate fertilizer; the coagulating bath is suitable to popularize and apply in scale for industrialized production.