The invention discloses an insulated boom type aerial live working tool for a strain insulator string. The insulated boom type aerial live working tool comprises an insulated boom type aerial, and is characterized by further comprising an insulated ladder and a bracket; the length of the insulated ladder is larger than or equal to the distance between a cage and the strain insulator string; the bottom of the insulated ladder is fixedly connected with the bracket; a fixed frame is arranged at the top of the insulated ladder; a steel cap of the strain insulator string is embedded in the fixed frame. The invention further provides an insulated boom type aerial live working method for the strain insulator string. The application range of the insulated boom type aerial for a transmission line is expanded, and the live overhaul efficiency in an electric power industry is improved.