Hydrogen cyanide (HCN), a major toxicant in cigarette smoke, was assigned as one of the 18 priority smoke constituent that should be regulated. Absorption is an effective method to remove toxic compounds from the cigarette smoke. However, the absorption from cigarette smoke was difficult due to that adsorbents need to operate under high flow rate at the gas-solid interface in the presence of thousands of other chemicals. By modifying the micro-structure and introducing functional groups to the adsorbents, the absorption ability could be enhanced via the chemisorption mechanism. Thus, chemisorption as well as the micro-structure adjustment may therefore represent a viable mechanism for the selective filtration of HCN in cigarette smoke. In this study, porous cellulose acetate/carboxymethyl cellulose (CA/CMC) composite microspheres were prepared via the combination of emulsion-solvent evaporation and in-situ cross-linking method. Cupric ions, which have high complexing ability to HCN, were introduced to the CA/CMC microspheres during the in-situ cross-linking process. The pore structure and surface chemistry of these microspheres were characterized using N2 adsorption/desorption, SEM/EDS and mercury intrusion porosimetry. The microspheres have a high cupric ion loading amount of 0.8~4.1wt% and a porous structure, which has connect pores and with much smaller crosslinked CMC microspheres in the caves of the CA/CMC composite microspheres. With these functional porous microsphere as filter additive agent, the HCN content in cigarette smoke could be reduced up to 27.3~50.1 % as compared to the cigarettes without any additive agent.