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 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 .