Abstract: It is known that a large amount of rare earth elements (REEs) is contained in phosphate rock, making it an important reserve of REEs after ion-type REEs ores. Therefore, it is significant to analyze and study the determination method for REEs in phosphate rock. Phosphate ore samples were digested with HF-HNO₃-HCl-H₂SO₄-aqua regia. A method for the determination of 15 REEs in phosphate ores by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) was established. Some parameters affecting the determination, such as sample weight, sample digestion method, selected determination isotopes and interference correction were investigated. Matrix effect and sensitivity drift were monitored and corrected by an interior isotope of ¹⁰³Rh. The recoveries of the method are 95.7%-108.0%, detection limits are 0.001-0.021 μg/g and precision (RSD) is less than 6% (n=12). The method is suitable for analysis of rare earth elements in phosphate ores.