The invention discloses a tire self-mending agent and a method for preparing the tire self-mending agent. The tire self-mending agent comprises, by mass, 30-40% of deionized water, 0.1-1% of polyvinyl alcohol, 0.5-1% of cellulose ether, 1-5% of plant fiber, 0.1-1% of nanometer inorganic filler, 40-50% of alcohol anti-freezing agent, 1-5% Read more......