  At large parallel magnetic field $B_\parallel$, the ground state of bilayer
quantum Hall system forms uniform soliton lattice phase. The soliton lattice
will melt due to the proliferation of unbound dislocations at certain finite
temperature leading to the Kosterlitz-Thouless (KT) melting. We calculate the
KT phase boundary by numerically solving the newly developed set of Bethe
ansatz equations, which fully take into account the thermal fluctuations of
soliton walls. We predict that within certain ranges of $B_\parallel$, the
soliton lattice will melt at $T_{\rm KT}$. Interestingly enough, as temperature
decreases, it melts at certain temperature lower than $T_{\rm KT}$ exhibiting
the reentrant behaviour of the soliton liquid phase.
