  Axion-like particles (ALPs) provide a feasible explanation for the observed
lower TeV opacity of the Universe. If the anomaly TeV transparency is caused by
ALPs, then the fluxes of distant extragalactic sources will be enhanced at
photon energies beyond TeV, resulting in an enhancement of the observed
extragalactic gamma-ray background (EGB) spectrum. In this work, we have
investigated the ALP modulation on the EGB spectrum at TeV energies. Our
results show that in the most optimistic case, the existence of ALPs can cause
the EGB spectrum to greatly deviate from the prediction of a pure
extragalactic-background-light (EBL) absorption scenario. The deviation occurs
at approximately $\gtrsim$1 TeV, and the current EGB measurements by Fermi-LAT
cannot identify such an effect. We also find that most of the sensitive ALP
parameters have been ruled out by existing constraints, leaving only a small
region of unrestricted parameters that can be probed using the EGB effect
investigated in this work. Observations from forthcoming very-high-energy
instruments like LHAASO and CTA may be beneficial for the study of this effect.
