A novel core-shell latex Gel Polymer Electrolytes (GPE) based on poly (methyl methacrylate-acrylonitrile -styrene) (P(MMA-AN-ST)) was prepared for applications in Li-ion batteries. The structure and the performance of the polymer and the GPE were characterized with FTIR, DSC/TG, TEM, SEM, LSV and CA. It is shown that the copolymer has a high thermal stability up to 320°C and the porous structure of the membrane was formed effectively. As-prepared gel polymer electrolytes exhibits a high ionic conductivity of 3.52×10−3 Scm−1 at 25°C and it is electrochemically stable up to 5.2V (vs. Li). This novel GPE can be potentially applied to the manufacture of PLBs.