The invention provides a cellulose acetate particle aggregation body and a preparing method and application thereof. The cellulose acetate particle aggregation body comprises 49-99.5wt% of cellulose acetate particles, 0-50wt% of second particles and 0.5-20wt% of binding agents. The preparing method includes the steps that the cellulose acetate particles and the second particles in certain proportions are selected, or only the cellulose acetate particles are selected, the binding agents are added for preparing particle aggregation bodies with the air fluidization prilling method, and the particle aggregation bodies are screened to obtain the cellulose acetate particle aggregation body with the needed particle size. Through the composition and physical forms, including the vesicular structure, the irregular shape, the rough surface and the rough and uneven surface, of the cellulose acetate particle aggregation body, the filtering efficiency of particular matter or one or more injurious ingredients in cigarette smoke is better improved.