Abstract: In the field of high-voltage cable accessories, insufficient surplus length of faulty lines and faulty line rapid repair have become the key problems to be solved, which seriously affects the stable operation of power system. In view of this, a lengthened type repair joint for 110 kV cross-linked polyethylene (XLPE) cables was developed. Using electric field analysis and mechanical analysis method, internal and external insulation of lengthened type repair joint was designed. Mechanical and electrical properties of lengthened type repair joint after design were comprehensively verified by cold and hot shock test, electrical assembly and other methods. Results showed that the repair joint could replace conventional intermediate joint to complete faulty line repair and improve repair efficiency.