All solid-state comb-like network polymer electrolytes (CNPE) based on poly(methylsiloxane) with pendant PEO chains as internal plasticizing chains (IPC) have been designed and synthesized. Ultraviolet (UV) polymerization method was applied for the curing of CNPEs. Effects of the network structure on the conductive properties and mechanical properties were discussed in details. Ionic conductivity of the prepared CNPE is one order of magnitude larger than those without IPCs, which suggests that the expected drop of conductivity caused by crosslinking has been well compensated by the introduction of IPCs. Maximum conductivity of 1.01×10−4 Scm−1 and maximum tensile strength of 0.66MPa were obtained at 30°C. Electrochemical stability and electrolyte/electrodes interfacial stability properties were evaluated by cyclic voltammetry and ac impedance, respectively.