The stellar halo of the Milky Way comprises only a small fraction of all stars in our Galaxy, but these stars are of high diagnostic value for probing the Milky Way’s dark matter halo and formation history. Stars extending to ~100 kpc make for an excellent dynamical probe of the halo mass profile, and the long dynamical periods at such large radii (~1 Gyr) mean that the dynamical formation imprint is still very apparent, e.g. in so-called sub-structures. However, Our knowledge of the halo is fragmentary, at least partly because of the paucity of halo stars, with known 3D  positions, radial velocities and abundances. Nowadays, with the development of large-scale sky surveys and space astrometry mission, such as 2MASS, SDSS, PanSTARRS1, LAMOST and Gaia, halo star samples are now of sufficient size and quality to boost the study of the Galactic halo. In this talk, I will show you how to map the Milky Way halo using blue-horizontal branch stars and K giants drawn from SDSS/SEGUE/LAMOST survey, such as the mass distribution of the dark matter halo, the shape and radial density profile, the metallicity distribution, and substructures of the stellar halo.