The objective of this research was to investigate the effect of immersion in Rhus verniciflua Stokes extract (RVSE) on the total reducing ability (TRA), protein oxidation and myoglobin oxidation of beef steak (Hanwoo longissimus muscle) stored with high oxygen-modified-atmosphere packaging (MAP) (HOMAP, 75% O2+20% CO2+5% N2) and low oxygen-MAP (LOMAP, 0% O2+20% CO2+80% N2) at 4℃ for nine days. RVSE induced TRA (p<0.05), metmyoglobin (MetMb) formation, and the CIE Ho value but reduced the carbonyl content and R630-R580, as an index of the intensity of redness by oxymyoglobin, and the CIE L*, a*, and C* values. HOMAP maintained a lower TRA, MetMb concentration, and CIE H° value but had higher R630-R580 and CIE L*, a*, and C* values compared to LOMAP. Therefore, RVSE induced TRA and protein oxidation stability but reduced myoglobin stability in Hanwoo beef steak. In addition, the effects of HOMAP were opposite those of RVSE.