  The Cauchy problem of the modified nonlinear Schr\"{o}dinger (mNLS) equation
with the finite density type initial data is investigated via
$\overline{\partial}$ steepest descent method. In the soliton region of
space-time $x/t\in(5,7)$, the long-time asymptotic behavior of the mNLS
equation is derived for large times. Furthermore, for general initial data in a
non-vanishing background, the soliton resolution conjecture for the mNLS
equation is verified, which means that the asymptotic expansion of the solution
can be characterized by finite number of soliton solutions as the time $t$
tends to infinity, and a residual error $\mathcal {O}(t^{-3/4})$ is provided.
