Graphene fiber-based supercapacitors hold great promise as flexible energy-storage devices.However,si-multaneously achieving high ion-transport ability in electrode and electrolyte layer,which is crucial for realizing the high electrochemical performance,still remains challenging.Here,a facile and effective strat-egy to solve the problem was proposed by developing a twisting-structured graphene/carbon nanotube(CNT)fiber supercapacitor via one-step wet-spinning process with customized multi-channel spinneret.The remarkable structure features of the resulting fiber supercapacitor with wrinkled and thin electrolyte layer,and well-developed porosity of fiber electrode favored the rapid infiltration and transport of elec-trolyte ions inside the electrode,as well as between electrode and electrolyte,thus boosting high specific capacitance of 187.6 mF cm-2 and energy density of 30.2 μWh cm-2,and featuring long cycling life(93％capacitance retention after 10,000 cycles)and excellent flexibility.Moreover,the specific capacitance and energy density could be further improved to 267.2 mF cm-2 and 66.8 μWh cm-2,respectively,when MnO2 was incorporated into the fiber.