  We propose to utilize the exclusive $Z$-boson rare decays $Z\to
\Upsilon(ns)+\gamma$ to constrain the $Zb\bar{b}$ couplings at the HL-LHC and
100 TeV proton-proton collider. We demonstrate that the event yield of the
proposed processes is sensitive to the axial-vector component of the
$Zb\bar{b}$ coupling and can provide complementary information to the
jet-charge weighted single-spin asymmetry measurement at the EIC and the $gg\to
Zh$ production rate measurement at the LHC. By applying the NRQCD factorization
formalism, we calculate the partial decay width of $Z\to \Upsilon(ns)+\gamma$
to the NLO accuracy in strong interaction, which is found to agree with those
obtained from the light-cone distribution amplitude approach. We show that the
HL-LHC can break the degeneracy of the $Zb\bar{b}$ couplings, as implied by the
precision electroweak data at LEP and SLC, if the signal efficiency can be
improved by a factor of 1.7 from the present ATLAS analysis at the 13 TeV LHC
with an integrated luminosity of $36.1~{\rm fb}^{-1}$.
