Amphiphilic rod-coil block copolymers containing polyethylene glycol and aniline oligomers can self-assemble into specific aggregation morphologies with different electrochemical performances, which have recently attracted more attention in many fields such as optoelectronic materials, electronics and so on. In this paper, the block copolymer of tetraaniline-polyethylene glycol-tetraaniline (ANI4-PEG-ANI4, PEG600, Mn＝600) was prepared using tolylene 2,4-diisocyanate (TDI) as intermediate. At first, tetraaniline was synthesised by 4-aminodiphenyamine through oxidative coupling reaction in an acidic solution. Then, TDI was used to combine tetraaniline and PEG to prepare the triblock copolymer in the presence of N,N-dimethylformamide (DMF). 1H-NMR and FT-IR were combined to confirm the chemical structure of the resulting block copolymer. The self-assembly of the block copolymer thin films was studied in detail. ANI4-PEG-ANI4 block copolymer was dissolved in a mixing solvent with ethanol and DMF. Then the solution was coated on conductive glass ITO to prepare thin films with the same thickness. And the films were dried completely before use. Atomic force microscope (AFM), UV-Vis spectroscopy and cyclic voltammetry (CV) were used to study the self-assembly behaviors of ANI4-PEG-ANI4 block copolymer thin films. The influence of mixing ratio of ethanol/DMF and different annealing solvents on the self-assembly behaviors of ANI4-PEG-ANI4 block copolymer thin films were investigated. The annealing solvents included ethanol, methanol, chloroform and tetrahydrofuran. The results showed that by changing the mixing ratio of ethanol/DMF, the morphologies of the block copolymer thin films could be changed from spheric to rod-like morphologies. And by changing the annealing solvents, the copolymer thin films could self-assemble into such as spheric, rod-like and fibrillar morphologies. The different aggregation structures of the block copolymer thin films exhibited different electrochemical performances. So the aggregation structures of ANI4-PEG-ANI4 block copolymer thin films could be tuned nicely by changing the solvents and annealing solvents.