We present new photometric observations covering eight minima times for the eclipsing binary GSC 1042-2191. The light curves in BVRI colors were analyzed by using WD-code for the system parameters. Eight minima times were obtained from the new observations. The system is found a low mass ratio (q = 0.148), A-type over-contact binary with a fill out parameter of f = 65.01 +/- 12.18%. The preliminary absolute dimensions (M-1= 1.26 +/- 0.06 M-circle dot, M-2 = 0.18 +/- 0.06 M-circle dot, R-1 = 1.54 +/- 0.20 R (circle dot), R-2 = 0.69 +/- 0.01 R-circle dot, L-1 =3.30 +/- 0.30 L-circle dot and L-2 = 0.59 +/- 0.20 L-circle dot) indicate the very much oversized and over-luminous secondary component, by assuming the present luminosity of the secondary is its main sequence luminosity, we predict the original mass is about 0.8 M-circle dot, this means the present secondary could be transferred and/or lost 77% of its original mass and only its core is left. (C) 2015 Elsevier B.V. All rights reserved.