The invention relates to a method for preparing high-purity hydrogen by reforming waste edible grease. The method includes the following steps of firstly, preparing a carrier, wherein metal oxide of a shell-core structure is used as the carrier for conducting reforming hydrogen production on waste edible grease; secondly, preprocessing waste edible grease, wherein swill-cooked dirty oil is deposited and filtered to obtain clear grease liquid; thirdly, making the grease liquid generate high-purity H2 in a fuel reactor through an oxidation-reduction reaction by controlling the circulation speed of particles of the metal oxide carrier and the flow of the grease liquid, and recovering the metal oxide carrier to the initial state to be recycled. Reforming hydrogen production is conducted on waste edible grease through the high-activity and anti-carbon-deposition sintered shell-core double-layer metal oxide carrier, the process is simple, the method is easy to operate and control, and the reaction process can be controlled by only regulating and controlling the temperature of the reactor or the fuel flowing speed.