After entering the new century, the demand for energy in human society is increasing day by day. Green energy is of great significance for maintaining the safety of human living environment and achieving sustainable development. Research and development of new electrode materials is an effective way to solve the problem of energy storage. In this paper, two-dimensional layered material Ti₃C₂T_x MXene was selected as the main material, and ternary sulfide halide semiconductor SbSeI was selected as the composite material. SbSeI/Ti₃C₂T_x MXene composite electrodes with different proportions were successfully prepared, and their properties were compared. It was found that the sample with 15 % composite ratio showed the best performance. The mass specific capacitance reached 871.4 F·g^-1 at the current density of 1 A·g^-1. The capacitance retention rate was still 63.7% at the current density of 20 A·g^-1, and the capacitance retention rate was still maintained at 96% after 5000 cycles. This study proposes a strategy to optimize the performance of MXene-based chalcogenide electrode materials, paving the way for the development of high-performance electrode materials with great potential in supercapacitor applications.