  We present the results of high-resolution spectroscopy of the extremely
luminous star CygOB2-No.12. We identified about 200 spectral features in the
range 4552-7939 AA, including the interstellar NaI, KI lines and numerous very
strong DIBs, along with the HeI, CII, and SiII lines. An MK spectral type we
derived for the object is B4.5Ia+. Our analysis of the radial velocity data
shows the presence of a gradient in the stellar atmosphere, caused by both
atmospheric expansion and matter infall onto the star. The Halpha emission
displays broad Thompson wings, a slightly blue-shifted PCyg type absorption
component and a time-variable core absorption. We conclude that the wind is
variable in time.
