To restrain agglomeration of nanoparticles in polishing powders and improve properties of polishing slurry, so as to achieve better polishing properties of optical glass such as polishing rate, surface roughness and so on, we add a kind of anionic surfactant Medialan into ceria polishing slurry and study the effects of Medialan mass fraction on size and dispersion of particles, and material removal rate, as well as surface roughness of polished optical glass. The results show that the addition of trace Medialan can significantly improve dispersion of particles in the polishing slurry, restrain agglomeration of ceria particles, and improve quality of the polishing slurry. When the mass fraction of Medialan is between 0 and 0.32%, the chemico-mechanical polishing rate increases firstly and then decreases with the increase of Medialan mass fraction. When the mass fraction of Medialan is 0.26%, the chemico-mechanical polishing rate reaches the maximum value of 122 nm/min. The surface roughness firstly decreases and then increases with the increase of Medialan mass fraction, and the surface roughness reaches the minimum value of 0.928 nm when the mass fraction of Medialan is 0.13%.