An inner tube (30) and an installation method, the inner tube comprising an inflatable ring (31), wherein the inflatable ring (31) comprises an outer ring inner tube layer (311) and an inner ring inner tube layer (312), the inner ring inner tube layer (312) is internally provided with a tire repair rubber bonding adhesive layer or a solid tire repair adhesive layer, a second inflatable cavity (313) is formed at an inner part of the inner ring inner tube layer (312), and a second valve (32) is disposed on the inflatable ring (31). In a state of air leakage, the annular tire repair rubber adhesive layer of the inflatable ring (31) will be blocked by means of the air pressure in the second inflatable cavity (313) and bond to an air leakage hole portion of the inflatable ring (31); the diameter of the inflatable ring (31) matches the diameter of an inner surface of an outer tube (20); and the inflatable ring (31) is supported on an inner surface of the left side of an upper portion or an inner surface of the right side of the upper portion of the outer tube (20), and the inflatable ring (31) may support the outer tube (20) in an inflated state.