  We present the results of the spectroscopic observations of HDE 226868, the
optical counterpart to the black hole X-ray binary Cyg X-1, from 2001 to 2006.
We analyze the variabilities of the two components in the complex H$\alpha$
line: one P-Cygni shaped component which follows the motion of the supergiant
and another emission component moving with an antiphase orbital motion relative
to the supergiant, which is attributed to a focused-stellar wind. The results
of KOREL disentangling of our spectra indicate that the focused stellar wind is
responsible for the major part of the variability of the H$\alpha$ emission
line. The emission of the supergiant component had a small difference between
the low/hard and high/soft states, while the focused wind component became
strong in the low/hard state and weak in the high/soft state. The wind is
nearly undisturbed by the X-ray photoionization during the low/hard state.
However, during the high/soft state, the X-rays from the compact object could
decelerate the line-driven wind and result in a high mass accretion rate, due
to the effect of the X-ray photoionization. The X-ray illuminating could also
change the temperature profile of the stellar wind and increase its
temperature, and thus decrease the H$\alpha$ emissivity of the wind, which
could explain the H$\alpha$ variabilities of Cyg X-1 during different X-ray
states.
