The work aims to explorethe air permeability and ductility of composite flexible interconnecting wires with porous polydimethyl siloxane (PDMS) substrates, so as to apply them in the medical field better. Three-dimensional digital image correlation (3D-DIC) method was used to detect the surface strain mismatch and out-of-plane displacement characteristics of the wires and the substrates during the uniaxial tensile process of composite flexible interconnecting wires with porous PDMS substrates of different porosity at 25 ℃. On this basis, the mean displacement (wm) and displacement amplitude (wa) were introduced as evaluation indicators to quantitatively characterize the out-of-plane deformation of composite flexible electrons. In addition, the evaluation indicators and the air permeability test results of the porous PDMS substrates were combined to evaluate the different wire samples. The results of this study indicated that the porous PDMS substrates could significantly reduce the out-of-plane deformation of the composite flexible electrons and make the composite flexible electrons have good air permeability. When the mass ratio of PDMS to deionized water was 6:1, the composite flexible interconnecting wires with porous PDMS substrates had stable out-of-plane deformation under the same tensile load (20 N) and the same tensile distance. The composite flexible electrons with porous PDMS substrates not only have good air permeability, but also can effectively enhance the degree of adhesion between the metal interconnect layer and the flexible substrate. The optimal doping mass ratio between PDMS and deionized water obtained can provide a reference for manufacturing high ductility flexible electronic devices with porous substrates.