The invention discloses a tearable sheathing canal, which comprises a round 
pipe, wherein the round 
pipe comprises two semi-cylindrical pipes symmetrical along the axis of the round 
pipe; the two semi-cylindrical pipes are matched by a heat sealing line; one opening end of the round pipe is sealed with an 
elastic membrane; the 
elastic membrane is provided with a through hole; and the round pipe is made of plastic. The tearable sheathing canal has the following beneficial effects that the sealing 
elastic membrane on the 
tail end of the sheathing canal can be used for effectively preventing air from entering a venous 
system because of negative pressure to cause complications such as 
pulmonary embolism when a patient inhales in the process that the tearable sheathing canal is sent into the venous 
system of the 
human body along a 
puncturing guide wire; when the tearable sheathing canal is sent into the venous 
system of the 
human body, possible air bubbles or 
thrombus in the sheathing canal can be sucked by a side pipe on the 
tail end of the sheathing canal, and anticoagulation 
heparin saline is injected; and when the a pace-making 
electrode conduit is conveyed to the venous system by the sheathing canal, the sealing elastic membrane on the 
tail end of the sheathing canal can be used for effectively preventing the air from entering the venous system to cause 
air embolism along with the 
electrode conduit.