Osmium surface was planarized by chemical mechanical polishing (CMP), the effect of different surfactants on the results of polishing was investigated via a series of home-made slurries. The influence of surfactants on the process of CMP was studied by electrochemical dynamics and X-ray photoelectron spectroscopy, the morphology of Os surface was characterized by atomic force microscopy (AFM). The results are following: when adding TMAOH in slurry, the MRR of Os decreases from 5.8 nm/min to 2.9 nm/min and the surface roughness (Ra) increases from 2.1 nm to 4.8 nm; although PEG400, SHMP and SDS can increase the MRR, they cannot improve the surface quality; SLS and CTAB can increase the MRR and decrease the surface roughness; especially, CTAB can increase MRR to 14.6nm/min and decrease surface roughness (Ra) to 0.57 nm.