The invention discloses an insulator string replacement assembly and an insulator string replacement method. The insulator string replacement assembly comprises a first mechanical arm, a W pin assembly and disassembly tail end, a second mechanical arm and an insulator string pushing tail end. According to the device and the method of the invention, insulator string replacement operation can be carried out in a live condition, hidden safety dangers are reduced to the minimal, the structure is simple, the operation is convenient, and popularization is facilitated.