[Objective] To explore the curative effect that replantation of completely disconnected thumb after power saw injury. [Methods] A retrospective analysis of 26 cases of power saw injury with thumb replantation after complete disconnect of the thumb. The survival rate and postoperative function were followed up afterward. [Results] Among the 26 cases in this group, 25 cases survived. According to the evaluation criteria for replantation of disconnected fingers regulated by the Chinese Medical Association Society of Hand Surgery in September 2000, 21 cases of the 25 cases of living fingers were excellent, 3 cases were good, 1 case was fair. The excellent and good rate was 84%. [Conclusion] For the replantation of completely disconnected thumb after power saw injury, the operation includes debridement under the microscope, fine anastomosis of blood vessels, multi-venous anastomosis, and complete hemostasis under the microscope. Through close observation after operation, the thumb survival rate of the patient is high, postoperative sensory and motor function recovery are ideal.