A method and device for forming a cigarette filter rod. The method is as follows: in a process of continuously conveying forward cigarette filter materials that tend to converge to have a rod shape, multiple granular additives are continuously output in accordance with a certain time interval, and are sprayed into the cigarette filter materials that converge forwards under the action of continuous transporting flows, so that after the cigarette filter materials converge to form a continuous filter rod, multiple groups of additive unit combinations formed of different granular additive units are embedded in an axial direction of the filter rod. With the method and device for forming a cigarette filter rod, a filter rod containing multiple granular additives can be formed in one step; multiple granular additives can be combined and arranged in any way along an axial direction of the filter rod; dosage positions and intervals of various granular additives can be adjusted and changed randomly; a production process is simplified and the production cost is reduced.