Abstract: Based on the core-shell structure design, flexible, stretchable, highly sensitive and stable polydimethylsiloxane silicone rubber@multiwalled carbon nanotubes/polydimethylsiloxane silicone rubber (PDMS@MWCNTs/PDMS) piezoresistive strain sensing fibers were fabricated via the simple and low-cost dip coating-curing method. The chemical structure, thermal stability and microstructures of silane coupling agent modified multiwalled carbon nanotubes (MWCNTs-KH570) were characterized by FTIR, XRD, TG and TEM. The effects of core-shell structure and MWCNTs-KH570 mass fraction on the electrical conductivity, the sensing properties and mechanical properties of the PDMS@MWCNTs/PDMS composite fibers, as well as the mechanics were investigated detailedly. The results show that KH570 is successfully grafted onto the surface of hydroxylation MWCNTs(MWCNTs—OH), leading to the good dispersibility and interface interaction in the shell layer PDMS matrix; The design of core-shell structure enables the PDMS@MWCNTs/PDMS composite fibers to have high electrical conductivity and sensing properties at the low filling; With increasing the MWCNTs-KH570 mass fraction, the PDMS@MWCNTs/PDMS composite fibers exhibit elevated electrical conductivity and sensing performances, and show superior repeatability and working stability in human joint motion monitoring.