  We discuss the event rate in DeepCore array due to neutrino flux produced by
annihilations and decays of galactic dark matter. This event rate is calculated
with a 10 GeV threshold energy, which is smaller than the threshold energy
taken in previous works. Taking into account the background event rate due to
the atmospheric neutrino flux, we evaluate the sensitivity of DeepCore array
for probing dark matter annihilation cross section and decay time. The
sensitivity studies include the annihilation modes $\chi\chi\to b\bar{b}, \
\tau^+ \tau^-$, \ $\mu^+\mu^-$, and $\nu\bar{\nu}$, and decay modes $\chi\to
b\bar{b}, \ \tau^+ \tau^-$, \ $\mu^+\mu^-$, and $\nu\bar{\nu}$. We compare our
results with corresponding constraints derived from observations of WMAP, ACT
and Fermi-LAT.
