Carbonatite can be divided into primary carbonatite and F—Ba rich type carbonatite. The later characterized by richment of volatile and alkaline earth element in magma, procuded many REE deposit, and has strong potential for oreforming. research of theory and experiment showed that F, Ba, and other alkaline earth, volatile are the key factor to induce the immiscibility among silicate, carbonate, or salt melts；and the immiscibility is better for richment of oreforming elements than fractional crystallization. Therefore, whether volatiles and alkaline earth elements are the key factor for F—Ba rich type carbonatite to mineralize? and is immiscibility the main mechanism for F—Ba rich type carbonatite to mineralize? This viewpoint only deduced from theory and experiment. It is necessary to test this point by studying typical deposit. The Weishan REE deposit in Shandong province with high enrichment of REE presents the character of high intensity of oreforming for F—Ba rich type carbonatite, and the Bayan Obo Fe—REE deposit presents the character of producing giant REE deposit for F—Ba rich type carbonatite. The two deposits are the ideal objects to understand the oreforming of F—Ba rich carbonatite magma.