  The Large High Altitude Air Shower Observatory (LHAASO) has reported the
measurement of photons with high energy up to 1.42 PeV from twelve gamma-ray
sources. We are concerned with the implications of LHAASO data on the fate of
Lorenz symmetry at such high energy level, thus we consider the interaction of
the gamma ray with those photons in cosmic microwave background (CMB), and
compute the optical depth, the mean free path as well as the survival
probability for photons from all these gamma-ray sources. Employing the
threshold value predicted by the standard special relativity, it is found that
the lowest survival probability for observed gamma ray photons is about 0.60,
which is a fairly high value and implies that abundant photons with energy
above the threshold value may reach the Earth without Lorentz symmetry
violation. We conclude that it is still far to argue that the Lorentz symmetry
would be violated due to the present observations from LHAASO.
