Herein, the effect of temperature on the frequency of the zero-group-velocity (ZGV) Lamb wave of an aluminum alloy sheet is studied. Further, an experimental system is established for the all-optical detection and excitation of the S₁-ZGV mode in an aluminum alloy sheet under different temperatures using a pulsed laser based on Doppler vibrometer. The S₁-ZGV mode frequency is observed to vary with the temperature in an aluminum alloy sheet. Subsequently, the experimental results denote that the frequency of the S₁-ZGV mode decreases by 10.4% when the temperature increases from 20 ℃ to 370 ℃, whereas the theoretical results denote that the frequency of the S₁-ZGV mode decreases by 10.9%. Therefore, the experimental results are observed to be consistent with the theoretical results. In addition, when the temperature increases from 20 ℃ to 370 ℃, the effects of the sheet thickness and shear wave velocity on the frequency of the S₁-ZGV mode are observed to be the smallest and largest, respectively, by considering the influences of the sheet thickness, Poisson ratio, and shear wave velocity of the aluminum alloy sheet on the frequency of the S₁-ZGV mode.