  The production cross sections of charmonia, charmonium-bottomonium and
bottomonia pairs in a single boson $e^+e^-$ annihilation have been studied in a
wide range of energies, which will be achieved at future $e^+e^-$ colliders
such as ILC and FCC. One loop QCD corrections to QCD and EW contributions as
well as their interference are considered. The both intermediate bosons
$\gamma$ and $Z$ are taken into account.
