Abstract: Laser-induced graphene (LIG) is a widely used electrode material for double-layer electric capacitors, while its relatively low electrochemical properties hinder its further applications. The addition of pseudocapacitive materials can effectively enhance the supercapacitor performance. In this paper, MnO₂/LIG composites were synthesized simultaneously by using laser direct writing on the surface of polyimide (PI) films coated with potassium permanganate (KMnO₄) solution. Tests show that the MnO₂ nanoparticles uniformly deposit on the porous structure of graphene, which made the MnO₂/LIG composites integrate the strong electrical conductivity of graphene with the high specific capacitance property of MnO₂. A planar flexible supercapacitor was assembled with the MnO₂/LIG composite structure as the electrode and polyvinyl alcohol (PVA)/H₃PO₄ as the gel electrolyte, demonstrating a specific area capacitance of 8.75 mF/cm² and a specific area energy density of 1.21 μW·h/cm² at a current density of 10 μA/cm². After 10000 charge/discharge cycles, the assembled supercapacitor keeps a capacitance retention rate of up to 93% and a coulometric efficiency of 86%. Moreover, the device shows excellent flexibility under different bending angles and good series/parallel connection characteristics, which can be arbitrarily combined to increase voltage and energy density, and thus greatly expands the application scenarios of flexible supercapacitors in the field of flexible energy storage.