Inhibititing effects of charge-transfer complexes (CTC) of hindered amine，such as，di-isopropylamine (DIPA) and 2，2，6，6-tetramethyl-4-piperidinol (TMP) to react with oh-loranil (CA) or benzoquinone (BQ) on radic al polymerization of methyl methacryhte (MMA)，initiated by azobisisobntylonitrile (AIBN)，has been investingated by dirlatometric method．The results showed that these complexes demonstrated greater inhibiting efficiency than those of quinones and hindered amines to be used alone Especially CTC formation of DIPA with CA COluld inhibite more remarkable the tpolymerization of MMA in presence of AIBN．In addkion．polymerization to be process in solvents such as benzene and acetonitrile were compared with those of ku]k polymerization of MMA．TIhose tests all reveal that CTC are polymerization inhibitors so that the efficiency of inhibition will be determined through the feasibility of CTC formation in polymerizating system．In other words，the re sults prov-ed prdiminary inhibition by the mixture of quinones and hindered amine for MMA might be also to involes electron-transfer from tie hindered amine into huinones forming CTC of hindered amine cation and semiqulnones anion．The semiquinones anions are

the actual inhibiting species．