Abstract: The skipjack tuna stored underdifferent frozen temperature (-18℃, -25℃, -33℃) and the freshness, myofibrillar protein and myoglobin of dark muscle during 9 months storage were investigated. The results revealed that TVBN of dark muscle under the temperature of-18, -25, -33℃ exceeded 30mg/100g on month 3, month 4, month 5 of storage, respectively. The increasing of K value was slowed by the lower temperature, and histamine was also controlled within the prescribed limits. The differences of myofibril fragmentation index (MFI) , shear force, myoglobin oxidation under diverse frozen storage temperatures were insignificant (p>0.05) , while the fat oxidation had significant difference (p<0.05) .