Polyaniline-poly[p-styrenesulfonic acid-co-methoxy-oligo(ethylene glycol)acrylate] composite (PANI-PSSA-co-MOEGA) electrode was prepared for an all-solid-state rechargeable lithium battery and a Li/PANI-PSSA-co-MOEGA model cell was fabricated by combining a cross-linked poly(ethylene oxide)-grafted poly(methylmethacrylate)RiClO(4) polymer electrolyte. PSSA-co-MOEGA dopant has anchored anion sites (benzenesulfonic acid site) for doping polyaniline and oligo-ethylene oxide side chains for improving the adhesion between the electrode and the polymer electrolyte. Li/PANI-PSSA-co-MOEGA cell exhibited good cyclability and high capacity over 40 cycles. A model cell was also assembled by using a polyaniline electrode doped with perchlorate anion, PANI-ClO4, and the capacity of Li/PANI-ClO4 cell decreases over 10 cycles. The differences are caused by two factors. First, the PANI-PSSA-co-MOEGA composite film became a partially cation-doped type polymer (by doping polymer anion). Second, the interface between the PANI-PSSA-co-MOEGA electrode and the polymer electrolyte is improved by incorporating the oligo-ethylene oxide side chains in both materials. The diffusion rate of the dopant ions in PANI-PSSA-co-MOEGA was faster than in the PANI-ClO4 film.