对时效状态不同的TC4合金在77～623K间进行了热循环试验，测定了热循环前后的拉伸性能结果表明：热循环1000次后，近峰时效态合金的强度下降，过时效态合金的强度变化最小，而塑性均显著下降.合金中的位错密度、层错和形变李晶的数量增多.在热循环过程中α格内激活的位错以型为主，激活的李晶以｛1011｝型为主. The results show that the tensile strength of TC4 alloy aged from 77 ℃ to 623K was measured before and after thermal cycling. The results show that after 1000 cycles of thermal cycling, the strength of the near-peak aged alloy decreases, The strength changes minimally and the ductility decreases obviously.The dislocation density, stacking faults and the number of deformed Li Jing increase in the alloy.The dislocations activated in the α lattice are mainly of the type in the thermal cycle, and the activated Li Jing is represented by { 1011} type based.