Fe3O4 nanoparticles were embedded into the surface of silk fibers for preparing effectively magnetic silk fabrics. Fe3O4 nanoparticles were applied onto silk fabrics by a swelling-fixing method in presence of the aqueous solution of ethylenediamine tetraacetic acid disodium salt (EDTA-2Na) and urea as swelling agent and the low concentration glutaraldehyde solution as fixing agent. The magnetic silk fabrics and raw silk fabrics were characterized by measuring X-Ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscope (SEM). The results confirmed that magnetic silk fabrics could be successfully obtained by a swelling-fixing method and the crystalline structure of silk wasn't seriously destroyed. The similar thermogravimetric curves and breaking strength showed that thermal stability and mechanical properties of treated fabrics were also highly preserved. Moreover, the magnetic properties and wash fastness of samples were also studied. It suggested treated silk fabrics had effective magnetic property, and the magnetizations decreased by 14.58% after multiple washing. •An effective way for fabricating magnetic silk fabrics by a swelling-fixing method.•Nanoparticles were embedded in the surface of silk fibers by swelling and fixing proteins without using any adhesion agents.•Magnetic silk fabrics exhibited excellent laundering durability.•The inherent thermal stability and mechanical properties of silk fabrics were highly preserved after they were treated.