Method for preparing cellulose fiber

The invention discloses a method for preparing cellulose fiber. By using melting spinning technology, the method comprises the following steps of: 1, mixing cellulose and ionic liquid in a mass ratio of 5-8:5-2 to obtain an uniform mixture, wherein the cellulose is wood pulp, cotton pulp or bamboo pulp with degree of polymerization of 400 to 1,000; the ionic liquid consists of cations and anions; the cations are substituent-containing alkyl imidazole ions, wherein the substituent is more than one of hydrogen, C1 to C6 alkyl group, ethyl, propenyl, butenyl, ethoxyl, hydroxypropyl and alkoxy groups; the anions are halogen ions, BF4-, PF4-, SCN-, CN-, OCN-, CNO-, CF3SO3-, CFCOO-, CH3COO-, and (CF3SO2)2N- or (CF3SO2)2Cl-; 2, feeding the mixture into a double-screw extruder for melting spinning and stretching the extruded yarn by 0.5 to 6 times; and 3, washing, performing thermal forming and winding to obtain the cellulose fiber.