  Two-photon radiative decay process $J/\psi \to 2\gamma+hadrons$ is studied,
and the main contribution processes $J/\psi \to 2\gamma + g g g$ and $J/\psi
\to 2\gamma + q \bar{q}$ are calculated. With the specific condition at the
BESIII, this rare decay process and the main background process $e^{+} e^{-}
\to \gamma \gamma + hadrons (q \bar{q})$ are investigated. The results show
that the ratio of signal to background can reach 1.24 with the optimized
selection criteria at the BESIII. In addition, a few distributions of the
signal and background are presented. All the results show that the signal is
large enough to be measured in the experiment.
