By combining living anionic polymerization and hydrosilylation, densely grafted bottlebrush polymers with controlled spacing of branch points are prepared. Dimethyl(4-vinylphenyl) silane and dimethyl(4-(1-phenylvinyl)phenyl)silane are anionically (co)polymerized to synthesize uniform, alternating, and gradient in-chain silyl-hydride (Si-H) functionalized backbones. The spacing of branch points is controlled effectively by regulating the distribution of Si-H groups along the backbones. Three backbones with a similar number of Si-H groups but variable distributions are used to synthesize corresponding bottlebrush polymers via hydrosilylation between the backbones and chain-end vinyl functionalized polystyrene. The uniformly grafted bottlebrush exhibits the highest hydrodynamic radius (R-h) of 5.6 nm and the lowest T-g of 79 degrees C which may be attributed to its compact grafted structure. This methodology exhibits high efficiency and convenience for the construction of bottlebrushes with controlled distribution of brushes.