  The cosmic antideuteron is a promising probe for the dark matter annihilation
signature. In order to determine the DM signature, the background astrophysical
antideuteron flux should be carefully studied. In this work we provide a new
calculation of the secondary antideuteron flux, and pay special attention to
the uncertainties from hadronic interaction models by using several Monte Carlo
generators. The uncertainties from propagation effects are also carefully
investigated for both the astrophysical background and DM annihilation
signature in several scenarios, which are constrained by the latest B/C ratio
measured by AMS-02. Considering these uncertainties, we find that the secondary
antideuteron flux is hard to detect in the near future detectors. However, the
antideuteron signature from dark matter annihilation will be detectable even
considering the constraint from the AMS-02 observation of the $\bar{p}/p$
ratio.
