The Precambrian Strata in Beijing and Dalian areas can represent Proterozoic sedimentary sequences of northern China. Since the discovery of authigenic monazite for the first time in the Shisanlitai Formation of Sinian System of Dalian area, we have discovered authigenic REE minerals of phosphate and silicate from the Changzhougou, Chuanlinggou and Dahongyu formations of Mesoproterozoic sedimentary rocks in Beijing area. There is a relationship between contents of REE in sedimentary rocks and presentation of authigenic REE minerals. According to the study of back scattered electron images and X-ray mapping of elements P, Th, La, Ce, Nd and Y by means of electron microscopic probe analysis, there are quite different properties between authigenic REE minerals and those from magmatic, metamorphic or associated heavy minerals of clastic sediments. This paper introduces for the first time the xenotime overgrowing on the clastic zircon grain margins in sedimentary rocks of the Changzhougou Formation, Changcheng System during the diagenesis process. Based on previous experiences there will be widely distributed authigenic REE minerals in Proterozoic sedimentary rocks of northern China, such as Jixian of Tianjin, western and southern Liaoning Province, and Xuanhua of Hebei Province. Those authigenic REE minerals can be used to determine their isotopic geological ages with the SHRIMP. Besides, in this paper we compared the similarity of crystalline forms and chemical compositions between the authigeneic monazite of the Sinian System, Dalian area and the monazite in host rock slate of eastern iron mining area of Bayan Obo, Inner Mongolia. So we once more emphasize the suggestion that the Proterozoic K- and REE-enriched sedimentary rocks in northern China may be the source rocks for the huge REE ore deposits in Bayan Obo, Inner Mongolia.