Flexible self-assembled membrane and hollow spheres (1.7–4.6 μm in diameter) accompanied with self-assembled membrane of poly(3,4- ethylenedioxythiophene) doped with acetic acid were synthesized in aqueous solution using ammonium persulfate as oxidant. Scanning electronic microscope imagines approved the flexible membrane and sphere-like morphologies and indicated a “grow from membrane” process. The mechanism of self-assemble phenomenonwas discussed by Fourier transform infrared and differential scanning calorimeter. Itwas found that self-assembly was driven by the hydrogen bond between 3,4-ethylenedioxythiophene monomers and acetic acid. The concentration of acetic acid plays an essential role in the self-assemble process. Moreover, the electrochemical properties of them with different morphologies were also characterized by cyclic voltammetry.