Abstract : Interstellar extinction is a serious obstacle for the interpretation of stellar populations in the Galaxy, especially for the low latitude regions, i.e. the Galactic disk and the Bulge. It shows an inhomogeneous clumpy distribution and increases towards the Galactic plane. The three-dimensional (3D) interstellar extinction mapping is an acknowledged and interesting aspect of Galactic astrophysics that has received increased attention again in the last several years, in particular in respect to upcoming data from Gaia, LSST and other very large surveys. We have constructed several 3D extinction maps for different regions in the Milky Way using different methods and different data sets. The 3D extinction maps are used to: a) investigate the dust and gas correlation of the Galaxy; b) constrain the Galactic structure; and c) obtain distance to objects like (SNR associated) molecular clouds. Finally, I would make a brief introduction of the ongoing LAMOST spectroscopic survey of the Galactic anti-centre (LSS-GAC).