  The absorption lines with high blue-shifted velocities are frequently found
in the ultraviolet (UV) and X-ray spectra of luminous active galactic nuclei
(AGNs). This implies that the high-velocity winds/outflows are common in AGNs.
In order to study the formation of high-velocity winds, especially ultra-fast
outflows (UFOs), we perform two-dimensional magnetohydrodynamic (MHD)
simulations. Initially, a magnetic field is set to be weaker than the gas
pressure at disk surface. In our simulations, line force operates on the region
like filaments, because the X-ray radiation from corona is shielded by dense
gas in the inner region at some angle. The location of filaments changes with
time and then the line-driven winds are in exposure to X ray and become highly
ionized. Line force at UV bands does not directly drive the highly-ionized
winds. In the sense of time average, the properties of high-velocity winds meet
the formation condition of UFOs. Compared with line force, the function of
magnetic field is negligible in directly driving winds. In the MHD model, the
region around the rotational axis becomes magnetic-pressure-dominated, which
prevents gases from spreading to higher latitudes and then enhances the gas
column density at middle and low latitudes (20$^{\rm o}$--70$^{\rm o}$). Higher
column density is helpful to shield X-ray photons, which causes that line force
is more effective in the MHD model than in the HD model. Higher-velocity winds
with broader opening angle are produced in the MHD model.
