  Within the context of the Littlest Higgs model with T-parity, the heavy
photon ($A_{H}$) is supposed to be an ideal dark matter (DM) candidate. One
direct proof of validity of the model is to produce the heavy photon at
collider. In this paper, we investigate the associated production of a photon
with heavy photon pair at the planned international $e^ +e^ -$ linear collider
(ILC), i.e., $ e^+ e^-\to A_{H}A_{H}{\gamma}$ and show the distributions of the
transverse momenta of the photon. The numerical results indicate that the heavy
photon production rate could reach several $fb$ at the low mass parameter space
and the characteristic signal is a single high energetic photon and missing
energy, carried by the heavy photons. All in all, it can be good chance to
observe the heavy photon via this process with the high yearly luminosity of
the ILC.
