Abstract: Three ZL114A aluminum alloys with different Ag contents were prepared. Then, they underwent solid solution treatment at 530 ℃ for 2 h followed by 540 ℃ for 12 h, and aging treatment at 175 ℃ for 9 h. Afterwards, they were left at room temperature for 48 h. Finally, they underwent thermal exposure tests at 130 ℃ and 190 ℃ for different durations. The effects of minor Ag on the microstructure and mechanical properties of ZL114A aluminum alloy after heat exposure were investigated by using universal electron tensile testing machine, scanning electron microscope and spherical aberration corrected field emission transmission electron microscopy. The results show that within 150 h of thermal exposure at 130℃has little impact on the mechanical properties of the alloys. When the heat exposure temperature reaches 190 ℃, the strength of the alloys decreases significantly and the plasticity increases. Adding Ag can improve the strength and thermal stability of the alloy. There is no obvious difference in the impact of Ag content of 0.34% and 0.55% on the mechanical properties of the alloy. The main precipitate of the alloys is β' phase after thermal exposure. Ag atoms are dissolved in the β' phase, which inhibits the growth of the β' phase and improves the high temperature stability of the alloy. When the exposure temperature reaches 190 ℃, the size of β' phase increases and the amount decreases, while the strength of the alloy decreases.