The invention discloses a method for preparing antibacterial functional cellulosic fibers. The method comprises the steps of using a cross-linking agent for enabling cyclodextrin to be arranged on the cellulosic fibers in a stem grafting mode through a chemical reaction, then utilizing the cyclodextrin on the fibers to conduct clathration on antibacterial agents, and in the preparing process, conducting ultrasound pretreatment on a reaction system comprising the cyclodextrin, the cross-linking agent, a catalyst and the cellulosic fibers. According to the method, the defect that in the prior art, the solid loading efficiency of the cyclodextrin is low, the preparation time is short, the efficiency is high, the antibacterial and anti-infection functional cellulosic fibers with the slow-release performance and paper products of the cellulosic fibers can be manufactured, and the functional cellulosic fibers have good market prospects.