Tectonically, Tex County is situated in the margin of Yili block within Yining central block of Yili-Yisaikehu microplate which belongs to the west section of Tianshan Orogenic Belt. Meso-Proterozoic Chancheng System in Tex is composed of Bolunganbulake, Mohexisayi and Zhumahansayi rock group. The rock is characterized by middle content of SiO2 and TiO2, high of (TFeO+MgO) and lower of CaO, Na2O. The chondrite-normalized patterns of REE show that HREE are concentrated, HREE flat, negative anomaly of Eu prominence. The source of main and trace elements is not single. On the basis of the fore-research, it is provided that Tex Rock Group was deposited in the basin at passive continental margin, and developed in rift environment of Atlantic continental margin.