Silver-coated fly ash cenospheres were embedded in silicone-rubber to form conductive composites. The electrical resistivity of the composites was examined and compared under different tensile strains. The electrical resistivity was a linear function of tensile strain under quasi-static load at linear viscoelastic area of the composites. Under cyclic strain, the peak of the electrical resistivity decreased and the offset was compared with the peak of strain and stress over time. For the stress relaxation test, the electrical resistivity displayed a change from linear to nonlinear under crescent transient strain. All of the changes were attributed to the breakup and rebuilding of the conductive networks in the composites.