In order to study the filtration and retention characteristics of crotonaldehyde in cigarette filters, the filtration efficiencies of crotonaldehyde were investigated in regular acetate filter under ISO and Health Canada Intense (HCI) smoking regimes, and in outer grooved acetate filter, inner grooved acetate filter, paper/acetate composite filter, ventilation cavity acetate filter under ISO smoking regime. The influences of smoking regime and filter structure on crotonaldehyde retention space distribution pattern were investigated. By on-line monitoring of the temperature of smoke flowing through the filters during the whole smoking process and the study of puff-by-puff crotonaldehyde retention longitudinal concentration distribution patterns, the filtration and retention characteristics of crotonaldehyde in filters were explained. The results showed that: 1) The filtration efficiency of crotonaldehyde in different filters under the ISO smoking regime from high to low order is: regular acetate filter > outer grooved acetate filter ≈ inner grooved acetate filter > paper/acetate composite filter > ventilation cavity acetate filter. The filtration efficiency of crotonaldehyde in regular acetate filter reduces remarkably under the HCI smoking regime. 2) The retention concentration distribution pattern of crotonaldehyde in filters is distinctly different from that of nicotine, phenol and other smoke components. Filter structures also have a notable effect on crotonaldehyde retention concentration distribution pattern in filters. 3) The puff-by-puff crotonaldehyde retention longitudinal concentration distribution pattern and smoke temperature on-line monitoring results showed that there was an adsorption-desorption-adsorption effect for crotonaldehyde in the smoking process, and this is the reason why the retention concentration distribution pattern of crotonaldehyde is significantly different from that of other smoke components.