Studies of nanoscale materials have captured significant scientific and industrial interest in recent years. Magnetic nanoparticles was prepared by FeCL3 and FeCl2(molar ratio 2:1) in distilled water and characterized by XRD, TEM. Hydroxyl groups of magnetite and modified by 3-aminopropyltriethoxysilane and acrylic acid was characterized by XPS, FT-IR. Magnetic moment was measured by VSM. Poly(acrylic acid) hydrogel embedded Surface Modified Magnetic Nanoparticles was prepared. The mechanical properties of -PAA hydrogel by texture analyzer in swelled state and swelling ratio was measured. Mechanical properties were increased, as content of magnetite was increasing.