Herein, the present work reports on the development of efficient sustainable and environment friendly cotton fiber composite material by oxidative polymerization of aniline via in-site approach using MnO2 as oxidating agent in acidic medium such as hydrochloric acid. The synthesized composite material was characterized by FTIR, FESEM and Cyclic Voltammetry (CV) investigation for their successful preparation and electrochemical performance for supercapacitor application. The presence of cyclic voltammogram, charge discharge cycle and lower charge transfer resistance of synthesized material shows good electrochemical behavior for supercapacitor application.