Disclosed is a chemical-mechanical polishing slurry composition having a small change in pH over time under an acidic condition and thus being easy to store for a long time. The chemical-mechanical polishing slurry composition includes an abrasive; an amount of about 0.000006 to 0.01 weight % of an aluminum component based on the total weight of the polishing slurry composition; and water. The number of silanol groups on a surface of the abrasive and a content of the aluminum component satisfy the requirements of following Equation 1: 0.0005≤(S*C)*100≤4.5,  [Equation 1] wherein, S is the number of the silanol groups present on 1 nm2 of the abrasive surface (unit: number/nm2), and C is the content of the aluminum component (weight %) in the slurry composition.