The　flexible　polyaniline　(PANI)　thin　films　with　modified　nanostructure　are　prepared　on　flexible　indium　tin　oxide　(ITO)/polyethylene　terephthalate　(PET)　substrates　by　combination　of　galvanostatic　and　cyclic　voltammetric　electrodeposition　techniques.　The　electrochemical　properties　of　as-prepared　PANI　nanomaterials　are　investigated　by　using　the　PANI　film　as　an　active　material　of　the　electrode　for　primary　electrochromic　device　and　electrochemical　supercapacitor.　This　film　presents　a　remarkable　mechanical　flexibility,　high　coloration　efficiency　of　80.9　cm(2)　C-1　at　630　nm　and　noticeable　multicolor　performances　with　reversible　color　change　of　transparent,　pale　yellow,　green,　blue　and　blue-purple.　Further,　a　smart　supercapacitor　is　presented,　and　the　level　of　energy　storage　can　be　monitored　by　the　change　of　optical　performance.　The　film　displays　the　highest　specific　capacitance　of　473.3　F　g(-1)　at　the　scan　rate　of　0.03　V　s(-1).　The　high-performance　PNAI　film　exhibits　promising　features　for　various　emerging　flexible　and　multicolor　electronics　and　optoelectronic　devices　combining　energy　storage　and　electrochromism.