The energy absorption of the 7075 alloy during low temperature impact was investigated at 0

-25℃

-50℃

-80 ℃

-120 ℃

respectively.It is found that with the decrease of temperature

the impact crack shape energy Eiof the 7075 alloy is gradually increased

while the impact crack instability expansion energy Eupof the 7075 alloy is gradually reduced

however

the total energy Eadd（Eaddis the sum of Eiand Eup）is relatively stable.The average strength energy Estunder high impact load is the main factor on the low temperature impact behavior of 7075 alloy

and the average strength energy Estunder high impact load is determined by the increase of the average impact load Faveand the change of the metastable extended displacement dstjointly.