Metasurface refers to a type of artificial thin film materials with sub-wavelength features that can generate the desired and/or new optical phenomena. The past decade has witnessed significant advances in the metasurface, ranging from fundamental physics to nanomanufacturing methods and practical applications. Typical research efforts include wave-front engineering and detection [e.g., Yu, Science 334, 333 (2011); Capasso, Nat. Commun. 3, 1278 (2012)], flat optics for focusing and imaging [e.g., Cappaso, Nano Lett. 12, 4932 (2012); Yu, Nat. Mater. 13, 139 (2014)], polarization manipulation [e.g., Zhan, Opt. Lett. 40, 4711 (2015); Sci. Rep. 6, 29626 (2016)], metahologram [e.g., Genevet, Rep. Prog. Phys. 78, 24401 (2015); Tsai, Nano Lett. 14, 225 (2014)], light trapping and localization [e.g., Gan, Adv. Mater. 26, 2737 (2014); Adv. Opt. Mater. 5, 1700223 (2017)], absorption engineering [Gan, Adv. Opt. Mater. 5, 1700166 (2017); Sci. Adv. 3, e1602783 (2017)], and colorimetric display. Being able to manipulate the optical properties of metasurfaces will create new regimes of optical physics and impact a broad range of photonic, energy, and biomedical technologies, including new commercial product research and development. Research and development efforts of these artificial thin film materials in promising areas continue to emerge. To capture the latest developments in this important emerging field of optics, it is our pleasure to introduce the Chinese Optics Letters Special Issue on Advances in Metasurface with contributions from scientists around the world who are active in this field.