The invention relates to cellulose solvent and a process for preparing spinning fluid. The solvent is prepared into homogeneous mixing liquid by the following formula under the temperature of 25-150 DEG C and the condition of stirring, the formula comprises N-methyl N-pi-allyl morpholine hydrochlorate which accounts for 1-99% of the total weigh of solvent, mixture accounts for 99-1% of the total weight of solvent, mixture is one of the following solvent: first, one kind of other species ion liquid or mixing liquid of a plurality of other species ion liquid, second, one kind of organic solventor mixing liquid of a plurality of organic solvent, third, mixing solvent of one or a plurality of ion liquid in first solvent and one or a plurality of organic solvent in second solvent. The processfor preparation comprises dissolving cellulose in solvent of the invention for 0.5- 50 hours under the temperature of 25- 150 DEG C, namely preparing cellulose spinning fluid, and concentration of the mass percent of cellulose spinning fluid is 1- 40%.