Transparent Nd:YAG ceramics which are very hard and brittle materials, are very difficult to be polished. There are many micro scratches or damages on the surface after mechanical polishing with Al2O3. In order to remove micro scratches or damages, chemical mechanical polishing (CMP) was adopted to manufacture Nd:YAG ceramics. In the polishing experiment, Pellon and Chemcloth pads were utilized for chemical mechanical polishing of Nd:YAG ceramics. Colloidal SiO2 was selected as the polishing slurry in two different polishing environments, acidity and alkalinity. The surface roughness was determined by using atomic force microscope. In this study, four polishing experimental combinations that each combination contains one of the two pads and one of the two polishing environments were carried out in the optimum polishing condition. Then the high quality surface of transparent Nd:YAG ceramics with the best surface roughness of < 0.2 nm RMS and few micro scratches or damages is obtained by adopting CMP process with Chemcloth pad and colloidal SiO2 in acidic condition.