As a major component of the LAMOST Experiment for Galactic Understanding and Exploration (LEGUE), LSS-GAC will survey a significant volume of the Galactic thin/thick disks and halo in a contiguous sky area (150d < l < 210d, -30d < b < 30d), and deliver spectral classification, radial velocity and stellar parameters for a statistically complete sample of ~ 3M stars down to a limiting mag. of r = 17.8 - 18.5. Together with Gaia, LSS-GAC will yield a unique dataset to advance our understanding of the assemblage of the Milky Way, particularly the Galactic disk(s). In this talk, I will summarize the current status of this project, focusing on its survey design, data collection and stellar parameter determinations, and present some early scientific results.