  Scalar mesons $a^0_0(980)$ and $f_0(980)$ can mix with each other through
isospin violating effects, and the mixing intensity has been predicted at the
percent level in various theoretical models. However the mixing has not been
firmed established on the experimental side to date. In this work we explore
the possibility to extract the $a_0-f_0$ mixing intensity using weak decays of
heavy mesons: $D_s\to [\pi^0\eta, \pi\pi] e^+\nu$, $B_s\to [\pi^0\eta,
\pi\pi]\ell^+\ell^-$ and the $B_s\to J/\psi [\pi^0\eta,\pi^+\pi^-]$ decays.
Based on the large amount of data accumulated by various experimental
facilities including BEPC-II, LHC, Super KEKB and the future colliders, we find
that the $a_0-f_0$ mixing intensity might be determined to a high precision,
which will lead to a better understanding of the nature of scalar mesons.
