Abstarct: 4-Nitrophenol (4-NP) has been listed as “priority pollutant” by US Environmental Protection Agency (EPA) because of its high solubility and stability in water. It stays longer time in water and surface soil without degradation and gets accumulated in deep soil indefinitely. The reduction of 4-nitrophenol by NaBH4 with silver nanoparticles is intensively studied by many researchers. In this research, to reduce 4-nitro-phenol، Poly (aminopropyl/methyl) silsesquioxane (PAMSQ) particles have been synthesized by a onestep hydrolytic co-condensation process using 3-aminopropyltriethoxysilane (APTES) and methyltrimethoxysilane (MTMS) as precursors in the presence of baxse catalyst in aqueous medium. Then, Ag nanoparticles was supported onto the surface of (PAMSQ) to produce (PAMSQ-Ag). Then it was thoroughly characterized by Fourier Transform Infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) along with Energy Dispersive X-ray (EDX) Spectroscopy, thermo gravimetric and differential thermal analysis (TGA), (CHN) Elemental Analysis and (ICP) Inductively Coupled Plasma Analysis. In order to study the catalytic activity of the as synthesized particles 4-NP (0.12 mmol/L) aqueous solution were stirred with freshly prepared NaBH4 solution (60 mmol/L). Then different amount of (PAMSQ-Ag) particles was added into the flask. UV–vis absorption spectra were recorded in different intervals to monitor the change of the reaction mixture at room temperature. The optimum conditions were found the equivalent amount of contaminants and reducing agents, with a 20 mg catalyst (PAMSQ-Ag), within 5 minutes.