The invention discloses a heat treatment method for an Al-Zn-Mg-Cu aluminum alloy. A solid solution-quenching-multistage aging system is adopted. The method includes the following steps that firstly,solid solution and quenching are performed, wherein a forged piece of the Al-Zn-Mg-Cu aluminum alloy is subjected to solid solution and quenching treatment, and the solid solution temperature is 470-478 DEG C; secondly, the first time of aging is performed, wherein the temperature of the first time of aging is 125 DEG C, and heat preserving time is 30-180 min; thirdly, rough machining is performed, wherein the forged piece after the first time of aging is subjected to water cooling, and then rough machining is performed; fourthly the second time of aging is performed, wherein the temperature of the second time of aging is 50-55 DEG C, and heat preserving time is 7-30 days; and fifthly, the third time of aging is performed, wherein the temperature of the third time of aging is 135-165 DEG C, and heat preserving time is 6-45 h. According to the heat treatment method for the Al-Zn-Mg-Cu aluminum alloy, strength is still kept at high level while the fatigue performance and the corrosion resistance of the aluminum alloy are improved.