  We present the first detailed photometric analysis of ATO J108.6991+27.8306
(hereinafter as J108). The short-period close binary J108 was observed by the
Nanshan 1 m Wide Field Telescope of the Xinjiang Astronomical Observatory. The
obtained BVRI-band light curves were used to determine the photometric solution
by using the 2003 version of the Wilson-Devinney code. J108 is a typical deep (
f > 50%), low mass ratio (q < 0.25) overcontact binary system with a mass ratio
of q = 0.1501 and a fill-out factor of f = 50.1 %, suggesting that it is in the
late evolutionary stage of contact binary systems. We found the target to be a
W-type W UMa binary and provided evidence for the presence of starspots on both
components. From the temperature-luminosity diagram, the main component is the
evolved main sequence star with an evolutionary age of about 7.94 Gyr.
