To provide a polishing slurry composition which effectively reduces the occurrence of scratches, and a method of polishing which reduces the occurrence of scratches while realizing an economical polishing step. The aforementioned object is attained by using a polishing slurry composition for polishing a semiconductor substrate containing a metal oxide particle, at least one water-soluble organic polymer and water, said slurry composition characterized in that, when a test substrate having a metal film, a shallow trench isolation film or dielectric film is polished by varying a rate of a polishing pad equipped in a polishing apparatus under a constant polishing pressure to achieve a maximum polishing rate.