  The halo stars on highly radial orbits should inevitably pass the center
regions of the Milky Way. Under the assumption that the stellar halo is in
dynamical equilibrium and axisymmetric, we integrate the orbits of $\sim
10,000$ halo K-giants at $5\leq r \leq 50$ kpc cross-matched from LAMOST DR5
and $Gaia$ DR3. By carefully considering the selection function, we construct
the stellar halo distribution at the entire regions of $r \leq 50$ kpc. We find
that a double-broken power-law function well describes the stellar halo density
distribution with shallower slopes in the inner regions and the two breaks at
$r=10$ kpc and $r=25$ kpc, respectively. The stellar halo becomes flatter from
outer to inner regions but has $q\sim 0.5$ at $r \lesssim 5$ kpc. The stellar
halo becomes isotropic with a slight prograde rotation in the inner 5 kpc, and
reaches velocity dispersions of $\sim 250\rm \ km\ s^{-1}$. We get a weak
negative metallicity gradient of $-0.005$ dex kpc$^{-1}$ at $5\leq r \leq 50$
kpc, while there is an excess of relative metal-rich stars with [Fe/H]$>-1$ in
the inner 10 kpc. The halo interlopers at $r \leq 5$ kpc from integration of
our sample has a mass of $\sim1.2 \times 10^8\ M_{\odot}$ ($\sim 4.7 \times
10^7\ M_{\odot}$ at [Fe/H]$<-1.5$), which can explain 50-100% of the metal-poor
stars with [Fe/H]$<-1.5$ directly observed in the Galactic central regions.
