  Exotic hadron states beyond the conventional $qqq$ baryon and $q\bar{q}$
meson configurations are well expected from QCD. Having been successful in the
past decades, the heavy quarkonium sector is proved to be an ideal place for
the study of exotic hadrons. In this talk, I briefly review the recent progress
on exotic heavy quarkonium-like state at $e^+e^-$ machines, including BESIII,
Belle/Belle II etc.
