The invention discloses an antistatic fiber and a preparation method thereof. The antistatic fiber comprises conductive parts and non-conductive parts; the conductive parts comprise a base polymer andconductive carbon black, wherein the carbon black accounts for, by weight, 25-40% of the conductive parts; the non-conductive parts comprise TiO2 and a fiber-forming polymer, wherein TiO2 accounts for, by weight, 2-30% of the non-conductive parts. The non-conductive parts and the conductive parts are both composed of monofilament fibers, the conductive parts and non-conductive fibers form the antistatic fiber, the conductive parts are distributed on the outer surface of the antistatic fiber in the fiber length direction, at least three conductive stripes are formed, and the conductive stripesare isolated through the non-conductive parts. According to the antistatic fiber, the conductive stripes are arranged on the surface of the fiber, the antistatic performance of the fiber is enhanced,the antistatic effect is durable, and the antistatic fiber is light-colored so as to bring convenience to coloring and post processing.