  The recent high energy electron and positron flux observed by the DAMPE
experiment indicates possible excess events near 1.4 TeV. Such an excess may be
evidence of dark matter annihilations or decays in a dark matter subhalo that
is located close to the solar system. We give here an analysis of this excess
from annihilations of Dirac fermion dark matter which is charged under a new
$U(1)_X$ gauge symmetry. The interactions between dark matter and the standard
model particles are mediated the $U(1)_X$ gauge boson. We show that dark matter
annihilations from a local subhalo can explain the excess with the canonical
thermal annihilation cross section. We further discuss the constraints from the
relic density, from the dark matter direct detection, from the dark matter
indirect detection, from the cosmic microwave background, and from the particle
colliders.
