Abstract: The silane coupling agent K570, liquid paraffin, PP, bronze powder were blended and granulated by a screw extruder, and dumbbell-like splines of different bronze powder contents were prepared by an injection molding machine. The thermal properties, morphology, mechanical properties and dielectric properties of the spline were analyzed by differential scanning calorimeter, field emission scanning electron microscope, universal strength machine and dielectric constant meter. The results show that with the increasing content of bronze powder, the crystallinity, breaking strength and elongation at break increase first and then decrease. When the content of bronze powder is 1.5 %, the breaking strength reaches a maximum of 49.98 MPa; when the content is 2 %, the elongation at break rises to the highest point of 426.3 %; in the ultrashort wave frequency range of 3.1×108~4.1×108 Hz, when the amount of bronze powder is 2 %, the real part of the dielectric constant of the spline is highest.