Oxygen consumption in different stages of Trichogramma dendrolimi during its development was studied. In embryonic period（24hours after oviposition） it was 1.385-1.955/μl/100insects/hr. In small larvae（48 hours after oviposition） this value decreased slightly at the range between 0.839μl/100 insects/hr. and 0.970μl/100 insects/hr. Then the value increased gradully with development and attained its maximum to 6.217-7.619μl/100 insects/hr, inprepupae. After pupation, the oxygen eonsumption again decreased gradully, and increased only slightly during late pupal stage（144 hours after oviposition）. It decreased once more after emergence. The changes of oxygen consumption showed a U-shaped curve during metamorphosis.