The invention provides a method for preparing Fe2O3 with a hollow structure based on microwave synthesis. The method comprises the steps that FeCl3.6H2O and urea are added into a three-mouth flask, and ethylene glycol is taken and added into the three-mouth flask; a magnetic rotor is added into the three-mouth flask and is fixed to a magnetic stirrer, and stirring is performed to make the FeCl3.6H2O and urea completely dissolved; the mixed solution is heated in a microwave reaction instrument and is subjected to thermostatic reaction; after reaction is completed, natural cooling is performed to room temperature, the obtained precipitate is centrifuged out, and repeated washing is performed with absolute ethyl alcohol and distilled water; the washed precipitate is subjected to vacuum drying, then constant-speed heating is performed, natural cooling is performed to room temperature, and finally a dry and loose red product is obtained. The prepared Fe2O3 with the hollow structure and serving as an electrode material has very good cycling stability, core-shell structure microspheres gathering together have larger specific surface area and facilitate iron penetration, and accordingly it is ensured that the material has better electrochemical properties.