The utility model relates to the technical field of
spare tire fixing, and discloses an automobile rear-row seat backrest
spare tire fixing device which comprises an automobile rear-row seat back plate and a
spare tire. According to the portable spare tire fixing seat, when a spare tire needs to be replaced, the spare tire can be detached only by unlocking a
ratchet wheel tightener and taking down a hook from a hanging ring, then the spare tire can be installed, when a new spare tire is installed, a sliding block can be slid to drive a movable plate to move, and the spare tire can be conveniently replaced. And a hanging ring is driven to move to adapt to installation of various spare tires with different sizes, then a
ratchet wheel tightener is tightened, a first triangular ring is pulled downwards, the
ratchet wheel tightener winds a binding column for winding, and therefore a first binding belt is driven to be tightened downwards to complete fixation of the spare tire. And meanwhile, after the distance is shortened, the first binding band and the second binding band can apply a force towards the back plate of the rear row seat of the automobile to the spare tire, so that the
friction force between the spare tire and the back plate of the rear row seat of the automobile is increased, and the spare tire cannot fall off.