The effects of benzaldehyde(BA)，p-nitrobenzaldehyde(PNBA)，m-nitrobenzaldehyde (MNBA)，m-bromobenzaldehyde(MBBA)，and p-ehlorobenzaldehyde(PCBA) on the poly-merization of acrylamide (AAM) in the presence of eerie ion (Ce4+) have been studied：Vinyl monomers such as AAM，acrylonitrile (AN) could polymerize using eerie ion (eerie ammoni-um nitrate) as an initiator．In the presence of eerie ion the rate of polymerization Rp of AAM could be enhanced by adding an aliphatic aldehyde to the polymerization system．Adding ben-zaldehyde，however，could not increase the Rp of AAM initiated by ceric ion．The Rp of AAM initiated by ceric ion/BA system is always lower than that of ceric ion alone．The values of overall activation energy of polymerization Ea were determined and the Ea values for ceric ion/MBBA and ceric ion/BA were evaluated to be 41.6 KJ/mol and 36.8KJ/mol respectively．The reaction of BA and ceric ion was investigated by UV spectra and the free radicalinterme-diate was detected by ESR spectrum．The end group of polymer formed was detected by IR spectrum analysis method and it revealed the presence of aliphatic aldehyde moiety in the polymer obtained with ceric ion/aldehyde system．