  We employ the Langevin equation and Wigner function to describe the bottom
equark dynamical evolutions and their formation into a bound state in the
expanding Quark Gluon Plasma (QGP). The additional suppressions from parton
inelastic scatterings are supplemented in the regenerated bottomonium. Hot
medium modifications on $\Upsilon(1S)$ properties are studied consistently by
taking the bottomonium potential to be the color-screened potential from
Lattice results, which affects both $\Upsilon(1S)$ regeneration and
dissociation rates. Finally, we calculated the $\Upsilon(1S)$ nuclear
modification factor $R_{AA}^{\rm rege}$ from bottom quark combination with
different diffusion coefficients in Langevin equation, representing different
thermalization of bottom quarks. In the central Pb-Pb collisions (b=0) at
$\sqrt{s_{NN}}=5.02$ TeV, we find a non-negligible $\Upsilon(1S)$ regeneration,
and it is small in the minimum bias centrality. The connections between
bottomonium regeneration and bottom quark energy loss in the heavy ion
collisions are also discussed.
