SrFe12O19/Zn0.65Ni0.25Cu0.1Fe2O4 core-shell nanocomposite has been successfully synthesized by sol-gel autocombustion (for SrFe12O19, core) and hydrothermal methods (for Zn0.65Ni0.25Cu0.1Fe2O4, shell). The products were characterized by X-ray powder diffractometer, transmission electron microscopy, fourier transform infrared spectrsocopy, vibrating sample magnetometer, Ultraviolet-visible specroscopy and inductively coupled plasma. Both X-ray powder diffraction, transmission electron microscopy results showed that Zn0.65Ni0.25Cu0.1Fe2O4 shell is on the surface of the SrFe12O19 core. The variations between the magnetic properties of the precursors and nanocomposite may be explained by interphase interactions at the surface of two ferrites. The properties of the SrFe12O19/Zn0.65Ni0.25Cu0.1Fe2O4 core-shell nanocomposite were favourable in its separation, recycling and reuse after reaction. The catalytic activity of SrFe12O19/Zn0.65Ni0.25Cu0.1Fe2O4 core-shell nanocomposite in the presence of NaBH4 were tested against methyl violet.