α-Fe2O3 particles with various morphologies,including micro-doublesphere,tetrakaidecahedron and nanoparticles-aggregated micro-ellipsoid,were successfully synthesized via an octadecylamine-assisted hydrothermal method.The products were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and high-resolution transmission electron microscopy(HRTEM).The results indicate that the presence of octadecylamine played a crucial role in morphology evolution by selective crystal adsorption.The protonated octadecylamine increased the pH value that accelerated nucleation,and the long alkyl groups of octadecylamine acted as an adsorption inhibitor to retard the growth of nanoparticles. The as-prepared α-Fe2O3 particles exhibited higher remanent magnetization and coercivity than other α-Fe2O3 particles of similar size.These properties should be attributed to the superstructure and the shape anisotropy of the synthesized particles. α-Fe2O3 particles with various morphologies, including micro-doublesphere, tetrakaidecahedron and nanoparticles-aggregated micro-ellipsoid, were successfully synthesized via an octadecylamine-assisted hydrothermal method. The products were characterized by X-ray diffraction (XRD) SEM) and high-resolution transmission electron microscopy (HRTEM). The results indicate that the presence of octadecylamine played a crucial role in morphology evolution by selective crystal adsorption. Protonated octadecylamine increased the pH value that accelerated nucleation, and the long alkyl groups of The as-prepared α-Fe2O3 particles showed higher remanent magnetization and coercivity than other α-Fe2O3 particles of similar size. These properties should be attributed to the superstructure and the shape anisotropy of the synthesized particles.