MXenes, a class of two-dimensional transition metal carbides and nitrides, have emerged as promising materials for supercapacitor applications due to their high electrical conductivity and hydrophilic surface chemistry. This typical chapter examines recent advances in MXene modification strategies, including surface functionalization, intercalation, and composite formation, to enhance their electrochemical performance. These modifications significantly improve specific capacitance, cycling stability, and rate capability. Particular emphasis is placed on the correlation between structural modifications and electrochemical properties, providing insights for the future development of high-performance MXene-based supercapacitors.