The invention discloses a device for preventing a blast hole from freezing. The device is composed of a sealing barrel, an inflation hose, a damper, a guide balance lead block, an inflation connector,a magnetic attraction connector, a safety rope, a tightening bag and a sealing sand bag. When the device is used, the device is straightly placed into the blast hole to be sealed, then constant-speedinflation is conducted, inflation is stopped after the volume of the sealing barrel is expanded to exceed the opening of the blast hole by 5-10 cm, the sealing barrel is clamped through calipers, then the sealing sand bag is pressed at a hole opening of the blast hole, and then the whole sealing treatment of the blast hole is completed. At the moment, the sealing barrel is tightly attached to thehole opening, the hole bottom and the whole peripheral wall of the blast hole, external surface water, rock mass crack water, rock mass seepage water and other water sources and air cannot enter theblast hole, and ice cannot be frozen naturally when no water exists. When the blast hole is filled with powder, the sealing sand bag is removed, and the sealing barrel is taken out for powder fillingoperation. According to the device, the blast hole can be sealed in an omnibearing manner, a water source causing blast hole freezing is effectively blocked, and the technical problem of blast hole freezing in blasting construction in plateau alpine regions is fundamentally solved.