The invention discloses a spherical mesoporous 
iron oxide and a preparation method thereof. The method comprises the following steps: adding certain amounts of CTAB and DDAB to water, dissolving the CTAB and the DDAB, adding a small amount of 
ammonia water, stirring, adding FeCl3.6H2O, continuously stirring to obtain a solution with a reddish brown precipitate, transferring the solution to a reaction kettle, placing the reaction kettle in a thermotank, carrying out a 
hydrothermal reaction, centrifuging the obtained product, washing the centrifuged product, 
drying the washed product, 
grinding the dried product, and calcining the ground product to obtain the mesoporous spherical 
iron oxide. The spherical mesoporous 
iron oxide with the surface having uniformly-distributed mesopores and with the inside being 
honeycomb is obtained by using a monocationic / dicationic surfactant as a composite template, the aperture is about 2-4nm, and the particle size is 200-250nm. The mesoporous spherical iron 
oxide prepared through the method has large adsorption ability to 
arsenic ions, lead ions and other ions, so the mesoporous spherical iron 
oxide is of great practical significance to develop efficient 
arsenic and lead removal adsorption materials.