The thermal stability and processing stability of polyaniline (PANI) as an electrode material is a spot widely concerned. This paper uses water-based polyurethane (WPU) as the polymeric substrate and uses in-situ polymerization to manufacture the PANI/WPU composite electrode material. Molecular structure, morphology of electrodes, thermal stability and polaron/dipole transition of PANI/WPU composites were observed. The results showed that the NH- group of aniline interacted with the NHCOO- group of WPU, and the PANI/WPU composite was prepared successfully. The PANI composite exhibits excellent electrical properties when its cyclic voltammetry curve is a nice rectangle with a ratio of 1:0.3 for WPU to aniline. When the current density is 1 A/g, the specific capacitance of the S3 sample reaches 473.3 F/g, which is much better than pure PANI. Compared with other composite materials, PANI/WPU has higher conductivity and good thermal stability. At the same time, PANI/WPU exhibits excellent chemical stability when used as an electrode material for concentrated cells. By solving the processing performance and thermal stability of PANI, it expands its applications in organic electronics.