Poly[siloxane-g-oligo(ethylene oxide)] tetraacrylate cross-linker was synthesized, and the gel polymer electrolytes (GPE) was prepared by thermal curing using them. Increase of conductivity with decrease of T g was observed as the content of liquid electrolyte increased. Maximum conductivity was found to be 3.92 × 10−3 S/cm at 30°C with a 70wt.% 1M LiPF6 in EC/PC (1:1). The electrochemical stability of the resulting gel polymer electrolyte could be extended to up to 4.4V. Applicability of the resulting polymer electrolyte for lithium battery was tested by Li|GPE|LiCoO2 cell.