Preparation method of highly curly viscose fiber

The invention discloses a preparation method of a highly curly viscose fiber. The preparation method comprises the following steps of (1) soaking, squeezing, crushing, aging, yellowing, grinding, filtering and defoaming cellulose pulp to obtain an initial viscose solution with a high alkali fiber ratio and a high ripening degree; (2) adding a delayed forming denaturant solution in a preparation process of the initial viscose solution, and fully mixing the denaturant solution and the initial viscose solution to obtain denatured spinning viscose; (3) performing spinning forming on the denaturedspinning viscose after a spinning bath to obtain nascent fiber tows; (4) carrying out plasticizing and drafting on the nascent fiber tows through a plasticizing bath at first, and then carrying out air bath drafting and cooling on the plasticized and drafted fiber tows in cold air; (5) refining, oiling and drying the drawn fiber to obtain a finished product of the highly curly viscose fiber. The highly curly viscose fiber