The invention relates to a microreactor applied to an ethyl alcohol and water vapor reforming reaction and a preparing method of the microreactor. The microreactor comprises spherical cerium dioxide and a Beta molecular sieve shell structure with the inner wall loaded with platinum, and an isolation hollow structure is arranged between spherical cerium dioxide and the Beta molecular sieve shell structure. The preparing method comprises the steps that a platinum source, an aldehyde compound, a phenol compound, a cerium source, polyvinylpyrrolidone, deionized water, absolute ethyl alcohol and the like serve as raw materials, poly diallyldimethylammonium chloride and sodium polystyrene sulfonate serve as treating agents, spherical cerium dioxide is synthesized first and then coated with phenol resin layers, high-temperature carbonization is carried out under the nitrogen condition, then spherical cerium dioxide coated with the phenol resin layers is treated with the treating agents, and finally the jingle-bell-type microreactor is synthesized. The jingle-bell-type microreactor applied to the ethyl alcohol and water vapor reforming reaction is simple, fast and controllable; according to the jingle-bell-type microreactor prepared through the method, the grain diameter ranges from 1.5 micrometers to 2 micrometers, and the product purity reaches 99.9%.