Abstract: A chemical mechanical polishing slurry for Ta barrier layer is disclosed, which comprises abrasive particles A, abrasive particles B larger in size than abrasive particles A, a triazole compound, an organic acid and a carrier. By using the chemical mechanical polishing slurry according to the present invention, the defects, scratches, contaminants and other residues can be reduced significantly, and the polishing selectivity between the barrier layer and the oxide layer can be adjusted by using particles of different sizes, so that the difficulty of adjusting the removing rates of two substrates separately is overcome. Furthermore, both the local corrosion and the general corrosion during the metal polishing process are avoided, and thus the yield rate of the desired products is promoted.