The development of shear-resistant drag reducer agent (DRA) is crucial for enhancing oil recovery, especially during high-speed pumping and fracturing processes where polymer networks are prone to damage, leading to the reduction of the drag reduction (DR) performance. To address this issue, the introduction of nano-silica into the polymer structure, while maintaining good DR, endows the DRA with better shear resistance and salt resistance through its unique cross-linking mode. In this study, a novel shear-resistant and fast-dissolving drag reducer was synthesized through free-radical polymerization using acrylamide (AM), acrylic acid (AA), 2-acrylamide-2-methylpropyl sulfonic acid (AMPS) and KH570 modified nano-silica. The comprehensive properties of drag reducer were studied using conductivity and dissolution time test, microscopic morphology analysis, thermogravimetric analysis, and rheological test. The results suggestion that the PAPO-10@SiO₂ exhibits outstanding characteristics, including rapid dissolution (4 min), excellent salt resistance (DR rate up to 80.41% at a polymer concentration of 500 mg/L) and nano-silica concentration of 1.5 wt%. Moreover, the mechanism of drag reduction was proposed that nano-silica connects the molecular chains through multiple cross-linking effects of chemical cross-linking and physical adsorption, which enhances the stability of the network structure and prevents the destruction of the molecular chain structure by shear force effectively (viscosity retention of 76.9% after shearing for 40 min at 90°C and 170 s⁻¹). In summary, this study provides valuable insights for developing polymers with both shear resistance and dissolution properties in aqueous solutions.