The invention discloses an automatic cutting device for a high voltage cable insulation layer and relates to the technical field of a power cable cutting device. The cutting device comprises an auxiliary mechanism, and a power mechanism, a control mechanism, a transmission mechanism and a cutting mechanism arranged on the auxiliary mechanism, wherein the transmission mechanism comprises a first transmission gear shaft system, the cutting mechanism comprises a blade arranged on the transmission mechanism, the transmission mechanism further comprises a positioning gear system, a second active gear of an electric motor unit is in mesh connection with a secondary gear of the positioning gear system, the cutting mechanism further comprises an elastic telescoping mechanism, the positioning gearsystem, the elastic telescoping mechanism and the blade are sequentially connected, the control mechanism further comprises an ultrasonic detection unit, and the ultrasonic detection unit and a controller are connected and realize bidirectional communication. The cutting device is advantaged in that through the electronic control technology, internal structures of the intelligent cutting power cable including an outer semi-conductive layer, a main insulation layer and an inner semi-conductive layer are realized, and properties of reliable operation, strong universality, firm structure and lowmanufacturing cost are realized.