The invention discloses a ham sausage casing-opening device. The ham sausage casing-opening device is characterized in that the device comprises a scabbard, a blade and a positioner, ends of the scabbard, the blade and the positioner are fixed by a rotating shaft, the scabbard, the blade and the positioner can respectively rotate around the rotating shaft, the lower long edge of the scabbard is opened, and is sunken to be arc-shaped to form an upper bayonet, and upper long edge of the scabbard is provided with a semicircular gap; the length and width of the blade are smaller than the length and width of the scabbard, and therefore the knife edge of the blade can be collected in the scabbard, and part of a knife back is exposed in the gap; the positioner is provided with a lower bayonet, the lower bayonet is sunken to be arc-shaped to accommodate the ham sausage, and an elastic piece is arranged in the lower bayonet and is suitable for clamping ham sausages with cross sections in different sizes. With respect to the ham sausage casing-opening device, the blade used for cutting up casings is collected in the scabbard, and therefore the ham sausage casing-opening device is safe and sanitary. At the same time, the ham sausage casing-opening device is simple and small, and can be added in a packaging bag of the ham sausage, and brings great convenience to a person who eats the ham sausage.