Abstract: In order to improve the electrochemical properties of graphene/polyimide (rGO/PI) composite yarn electrode, polyaniline (PANI) particles were deposited on the surface of rGO/PI composite yarn by electrochemical polymerization, and the effect of deposition time on the morphology and weight gain of PANI-rGO/PI composite conductive yarn was studied. As a result, PANI is deposited uniformly on the surface of the rGO/PI composite yarn, and the deposition amount increases with the deposition time increasing. The electrochemical behavior of PANI-rGO/PI composite conductive yarns was studied by cyclic voltammetry (CV) and galvanostatic discharge-charge method (GCD). The results show that the PANI deposition time has a great influence on CV and GCD characterastics. When the deposition time of PANI is 900s, the CV characteristics and GCD performance of the electrode of PANI-rGO/PI composite yarn are optimal, with a specific capacitance of 81.22 Fcm^-3, while the electrode of rGO/PI yarn is only 16.4 Fcm^-3. The PANI-rGO/PI composite conductive yarns with optimal process were assembled into a fiber-shaped supercapacitor, the electrochemical properties of the fiber-shaped supercapacitor were studied through the electrochemical impedance spectroscopy (EIS), CV and GCD. The results show that the volume specific capacitance of the device can reach 41.73 Fcm^-3, and the device shows an excellent long-life performance up to 3000 times with a retention of~85%. The PANI-rGO/PI fiber-shaped supercapacitors can be readily connected in serial to power LED.