Abstract: The latest developments on the preparation methods and applications of Fe₃O₄ nanoparticles are reviewed in this paper. The focus was paid on the research status of Fe₃O₄ nanoparticles and their composite materials in the fields of wastewater treatment, chemical catalysis, energy storage and biomedicine. At the same time, the challenges and possible future development trends of Fe₃O₄ nanoparticles in the current application process are discussed.