Magnetite (Fe3O4) nanobranches were synthesized using an improved solvothermal technique in mixed ethanol and water solvent. Structural and magnetic properties were systematically investigated. X-ray diffraction results showed that the sample was single-phase spinel structure. The results of scanning electronic microscopy exhibited that the grains were regular like-branch with sizes from 3 to 6 μm in length and in diameter between 50 and 200 nm. The composition determined by energy dispersive spectroscopy was very close to the stoichiometry of Fe3O4. The saturation magnetizations (Ms) at 10 and 300 K of the synthesized Fe3O4 nanobranches were much lower than the theoretical values. On one hand, it could be explained by obstructive magnetizing along their non-easy magnetic axes by the shape anisotropy of Fe3O4 nanobranches, on the other hand, lesser Ms can also be understood by the existence of antisite defects.