Phenolic compounds, such as phenol, cresols, catechol and resorcinol, are included in the so-called "Hoffmann" list of the most hazardous compounds found in cigarette smoke. It is considered desirable to potentially reduce the delivery of these compounds to the smoker. Therefore, a novel polycationic composite material with moisture retention ability was developed and applied to reduce the phenolic compounds in cigarette smoke. The hydrophilic polycationic material, poly (vinyl galactose ester-co-methacryloxyethyl trimethylammonium chloride) was synthesized and assembled with sodium alginate on activated carbon by layer-by-layer assembly technique to construct a moisture retention film. The formation of the multilayer was followed by the determination of water contact angles and the composite material with the multilayer was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis. The moisture in the composite material could be controlled and retained in the range of 0 to 35%; when temperature increased to 100 °C, only less than 5% of moisture was lost. When relative humidity was higher than 50%, moisture could be hardly lost. Furthermore, the composite materials added to cigarette filter could reduce more than 70% of seven phenolic compounds in mainstream cigarette smoke.