For the explosion-proof weak points at the end of the intermediate joint of high-voltage cables，an optimization design method for the end of the explosion-proof copper shell was proposed.By using a finite element calculation method coupling the temperature field，displacement field，and flow field，the stress concentration factor K at the copper shell end of the joint under different deflection angles α was calculated；then，under the deflection angle with the minimum stress concentration factor，circularization and copper shell thickness coordination design were conducted.Orthogonal experimental design is conducted on the two arc curvature radii and the thickness of the explosion-proof copper shell of the cable joint，and virtual objective optimization is performed taking the maximum stress borne by the copper shell and the copper shell mass in the end region，which represent safety and economy，as indicators.Taking the 220 kV explosion-proof high-voltage cable joint as an example，the optimal deflection angle α = 123°，optimal radii of curvature R1 = 130 mm and R2 = 40 mm，and copper shell thickness h = 3.0 mm are obtained.By comparing with the copper shell end with deflection angle α = 123°，it is obtained that the maximum stress borne by the optimized end decreases to 28%，and the average stress decreases to 44%.The circularization design has a significant effect in reducing stress，greatly improves the explosion-proof performance and safety margin of the intermediate joint of high-voltage cables，and can provide a basis and design method for the end design of explosion-proof high-voltage cable joints.