Abstract: In the field of high-voltage cable accessories, insufficient surplus length of faulty lines and the rapid repair of faulty lines have become key problems to be solved. This problem seriously affects the stable operation of the power system. In view of this, a lengthened type repair joint suitable for 110 kV XLPE cable was developed. Using the electric field and mechanical analysis method, the internal and external insulation of lengthened type repair joint was designed. After lengthened type repair joint was designed completed, mechanical and electrical properties were comprehensively verified by cold and hot shock test, electrical assembly and other methods. The repair joint could replace the conventional intermediate joint to complete the repair of faulty lines and improve the repair efficiency.