To prepare a high-performance flexible hybrid supercapacitor, MXene nanosheets were synthesized via chemical etching. Combined with polyaniline (PANI) and activated carbon (AC), the flexible AC/Mxene/PANI (CMP) composite electrode was fabricated through a physical rolling process after the uniform mixing. As a framework material with a high specific surface area, AC effectively provided loading and active sites, while MXene established ion transport channels. PANI, as a conductive material, accelerated charge transfer between MXene layers. Additionally, the introduction of MXene and PANI significantly enhanced the electrochemical performance of composite electrode due to their excellent pseudocapacitive behavior and increased active surface area. It demonstrated that the CMP-50% (with a mass ratio of AC, MXene and PANI is 2∶1∶1) electrode, having a thickness of 75 μm, exhibited a high capacitance of 313 F/g in sulfuric acid electrolyte at a scan rate of 1 mV/s. Furthermore, it maintained a high capacitance retention rate of 80.9% and a Coulombic efficiency of 98.4% at 5 A/g current density. The introduction of MXene and PANI significantly enhanced the electrode's capacitive performance and conductivity, opening up a new path for the development of high-performance flexible hybrid supercapacitors.