The invention discloses a deicing device for a high-voltage line, and relates to the technical field of auxiliary tools of power facilities. The deicing device consists of a control box (6), rollers (5), a telescopic sleeve (7), an ice breaking sleeve (8) and a deicing knife (3), wherein the rollers (5) and the telescopic sleeve (7) are arranged on the control box (6); the telescopic sleeve (7) is arranged at one end of the control box (6), extends into the control box (6) and is connected with the control box (6); a movable shaft (2) is arranged at the other end of the control box (6); the telescopic sleeve (7) is connected with the ice breaking sleeve (8); bristles (11) are arranged on the ice breaking sleeve (8); a fixed shaft (1) is arranged on the movable shaft (2); balls (14) are arranged between the movable shaft (2) and the fixed shaft (1); and the deicing knife (3) is arranged on the fixed shaft (1). The deicing device for the high-voltage line is high in practicability and easier to use, and can automatically and efficiently protect the high-voltage line from being damaged by outer force; and the service life of the high-voltage line is prolonged, and the cost and the labor investment are greatly saved.