The invention relates to a method of preparing a cellulose fibre releasing anions by using the solvent method and the application. The method has the following steps: firstly, the comminuted cellulose, tourmaline powder and addition agent are well mixed with an ironic liquid, dissolved at a temperature of 35 to 160 DEG C, deaerated for 1 to 120 hours and a homogeneous and stable spinning solution with a total solid content of 3 to 30 percent is formed, wherein, the mixed mass ratio of the tourmaline powder is 0.01 to 20 percent and the added mass ratio of the addition agent is 0 to 10 percent; secondly, the spinning solution is filtered, deaerated, spinned and solidified through a coagulation bath; and thirdly, a composite fibre of cellulose and tourmaline powder is obtained after the procedures of stretching, water cleaning, bleaching, oiling and drying. The composite fibre has the functions of releasing anions, generating far infrared radiation, generating biocurrent and suppressing bacteria and is applicable to the fields of garments, ornaments and medical textiles. The ironic liquid used in the invention has high production efficiency, is easy for callback and conforms to the requirement of a green production. The prepared composite fibre has excellent mechanical strength and mechanical property, and the fabric made of the composite fibre can release anions, resist bacteria and prevent mildew.