The oxidation and polymerization for the system of triethylenedimethaerylate (TEGMA)-dimethyltoluidine (DMT)，triethylenediaerylate(TEGA)．DMT，2-hydroxypro-pylmethaerylate (HPMA)-DMT in the presence or absence of oxalic acid have been studied．The results show that oxalic acid posseses much high antioxidizing and inhibi-ting power than hydroquinone，therefore，it is an effective antioxidant and inhibitor for the system of acrylic ester-amine．The chief function of oxalic acid would be antioxidation．since the oxidation of the system of acrylic ester-amine in the presence of small amount of oxalic acid will nearly stop，therefore the accumulation of the peroxide be comes very difficult．This may be the reason for the stability of this system as we]l as the others such as polypro-pylene and polyamides etc．in the presence of small amount of oxalic acid．