Hollow porous magnetite spheres were synthesized by a simple solvothermal route with controllable size ranging from 80 nm to 400 nm. The size, shell thickness and the interior space of the resulted crystals were controlled by reaction time, molar ratio of ammonium bicarbonate (NH4HCO3) and ammonium acetate (NH4Ac). The structure, morphology, size, and magnetic properties of the hollow porous magnetite spheres were investigated. The characterizations of Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) images showed that ratio of NH4HCO3 and NH4Ac, and molar concentration of ammonium played an important role in the morphology, size and magnetic property of the porous hollow sphere. Meanwhile, reaction time strongly influenced in the porous structure and interior space of hollow porous magnetite spheres.