  In this paper, we present the first results obtained using $\sim$ 50 ks
observations of the bright low-mass X-ray binary (LMXB) GX 17+2 with Large Area
X-ray Proportional Counter (LAXPC) onboard {\it AstroSat}. The source traced
out a complete Z-track in the hardness intensity diagram (HID). The spectra at
different sections of the Z-diagram are well described by either a combination
of a thermal Comptonization component, a power-law and a relativistic iron line
or a model consisting of a thermal disk component, a single temperature
blackbody, a power-law and a relativistic iron line. Fitting the spectra with
both phenomenological models suggests that the power-law component is strong in
the horizontal branch (HB), becomes weaker as the source moves down the normal
branch (NB) and then again becomes stronger as the sources moves up the flaring
branch (FB). However, we find that the strength of the power-law component is
model dependent, although the trend in the variation of the power-law strength
along the Z-track is similar. A simple model composed by a Comptonized emission
and power-law component, convolved with the ionized reflection, also describes
the spectra very well.
  A normal branch oscillation (NBO) with a centroid frequency 7.42$\pm$0.23 Hz,
quality factor (Q) $\sim$ 4.88, rms 1.41$\pm$0.29\% and significance
5.1$\sigma$ is detected at the middle of the NB. The parameters of the
Comptonized emission show a systematic evolution along the Z-diagram. The
optical depth of the corona increases as the source moves up along the FB,
suggesting possible trigger of an outflow or dumping of the disc material in to
the corona by radiation pressure.
