LaF3 and LaF3: Re (Re= Ce3+, Eu3+ and Tb3+) nanocrystals have been successfully synthesized by a facile and rapid microwave heating method. The structure, morphology and fluorescent properties of the as-prepared products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and photoluminescence spectroscopy (PL). XRD patterns showed that the undoped and doped LaF3 nanocrystals had hexagonal structure with good crystallinity and high purity. TEM and HRTEM images showed that the LaF3 nanocrystals have uniform sizes with mean diameter about 20 nm and are characteristic of inner cavities. The luminescence spectra of the LaF3: Re (Re= Ce3+, Eu3+ and Tb3+) nanocrystals indicated that different rare-earth ions have been successfully doped in LaF3 matrix via the microwave heating method.