Abstract: Stretchable strain sensors have broad application prospects in the field of vibration reduction and isolation, however, developing low-cost and high stability stretchable strain sensors remains a huge challenge. This article used the open melt method to prepare multi-walled carbon nanotubes (MWCNT)-conductive carbon black (CB)/methyl vinyl silicone rubber (VMQ) conductive nanocomposites. The effects of the synergistic effect between MWCNT and CB on the dispersion, conductivity, mechanical properties and resistance-strain response of the composites were investigated.The results show that the mechanical properties of the composite material are improved after adding CB, with a lower percolation threshold (1.24wt%), and excellent resistance strain response stability is demonstrated during 5000 cycles of loading-unloading. In addition, compared to MWCNT/VMQ and CB/VMQ composites, the MWCNT-CB/VMQ composite did not exhibit shoulder peak phenomenon in the resistance-strain response performance, and explained the mechanism of shoulder peak phenomenon. Through SEM, it is found that the uniform distribution and synergistic effect of MWCNT and CB in the composite material are important reasons for the low threshold and stable resistance-strain response performance. The mechanism of resistance-strain response was explained through the tunnel effect theory model. This composite material has great potential for strain monitoring of seismic isolation structures.