The invention discloses a cylindrical device for stripping a main insulating layer of a power cable. The cylindrical device for stripping the main insulating layer of the power cable comprises a blade (1), a positioning cylinder (2) and a limiting sleeve (3), wherein a long strip-shaped cutting edge is formed on one side of the blade (1), a long strip-shaped blade embedding opening which penetrates through the side wall of the positioning cylinder (2) is formed in the positioning cylinder (2), the blade (1) penetrates through the blade embedding opening, the cutting edge of the blade (1) is located in the positioning cylinder (2), and the positioning cylinder (3) is sleeved with the limiting sleeve (3). By the adoption of the structure, the cylindrical device for stripping the main insulating layer of the power cable is simple in overall structure and convenient to obtain. When the cylindrical device is used for stripping the main insulating layer of the power cable, operation is fast and convenient, and an inner core of the cable can be prevented from being damaged.