A novel type of polymer brushes as a stabilizing agent was synthesized by benzylamine at room temperature. The synthesized polymer brushes can act as an excellent stabilizing agent and the method of synthesis is also a simple one. Three different types of magnetically recoverable nano-catalysts were prepared through individual immobilization of silver nanoparticles (Ag NPs) onto the surface of Fe3O4 NPs, Fe3O4-OA NPs and Fe3O4-PBA NPs viz., Fe3O4-Ag NPs, Fe3O4-OA-Ag NPs, Fe3O4-PBA-Ag NPs catalysts, respectively. The synthesized catalysts were characterized by XRD, H-1 NMR, GPC, Raman, FT-IR, UV-vis, VSM, SEM and HR-TEM. The catalytic potential of the newly prepared catalyst was examined through the reduction/degradation of methylene blue by NaBH4 under pseudo-first order reaction condition. The apparent rate constant (K-app) and TOF of Fe3O4-Ag NPs, Fe3O4-OA-Ag NPs, Fe3O4-PBA-Ag NPs are 2.0 x 10(-2) s(-1), 3.3 x 10(-2) s(-1), 15.6 x 10(-2) s(-1) and 5.0 x 10(-3) s(-1) 83.3 x 10(-3) s(-1), 285.7 x 10(-3) s(-1) respectively. Among the catalysts, based on K-app value, catalytic activity of Fe3O4-PBA-Ag NPs (15.6 x 10(-2) s(-1)) is eight times higher than Fe3O4-Ag NPs (2.0 x 10(-2) s(-1)). The Fe3O4-PBA-Ag NPs catalyst was tested to estimate the material stability up to seven runs without losing catalytic activity by recovery catalysts. This new method of prepared catalysts is expanded for the application of magnetic recoverable nano-catalysts in various industrially important reactions because of its simple preparation method along with its recyclable capacity and high activity.