The invention discloses a method for preparing a mesoporous structure tin oxide fiber gas sensitive material from plant seed fiber fluff as a template, in particularly, Asclepiadaceae seed fiber fluff is used as the template, ethanol-water is used as a mixed solvent, after titration, a solvothermal method is used for synthesis, by copying of the special microstructure of the Asclepiadaceae seed fiber fluff, the particle size of the synthesized tin oxide is reduced, in the calcination process, Asclepiadaceae seed biological tissues are oxidized and removed to leave pores, experiments prove that the specific surface area of the mesoporous structure tin oxide fiber gas sensitive material prepared by the method is as high as 73.665m<2> / g, the average pore size is 7.82nm, because of high powder surface activity and large surface area and high gas penetration, the gas sensitivity of tin oxide is significantly improved, and the selectivity is improved.