The invention relates to a Pt-modified SnO2 nanorod sensor, and a preparation method and application thereof, and belongs to the technical field of inorganic nano functional materials. The Pt-modifiedSnO2 nanorod sensor provided by the invention adopts hydrothermal synthesis, self-assembly technology and ultra-long treatment, so that the nanorods have better crystallinity and higher draw ratio, and self-assembly is more likely to occur. Then, the Pt nanoparticles are uniformly modified on the SnO2 nanorods by ultraviolet light reduction, thereby enhancing the high-sensitivity rapid response of the SnO2 nanorods to hydrogen. The sensor devices assembled in this way can generate a relatively obvious change in resistance values in an environment with relatively lower hydrogen content h at room temperature, thereby obtaining a sensor for rapidly measuring hydrogen concentration at normal temperature.