Well-defined 3D Fe₃S₄ flower-like microspheres were synthesized via a simple biomolecule-assisted hydrothermal process for the first time. On the basis of a series of contrast experiments, the probable growth mechanism and fabrication process of the products were proposed. The electrical conductivity property of the as-synthesized Fe₃S₄ sample exhibited a rectifying characteristic when a forward bias was applied for the bottom-contacted device. The magnetic properties of the products were studied as well and the results demonstrated that the products presented ferromagnetic properties related to the corresponding microstructure. In addition, we first verified that the Fe₃S₄ flower-like microspheres could store hydrogen electrochemically, and a discharge capacity of 214 mA h g⁻¹ was measured without any activation under normal atmospheric conditions at room temperature.