Through the trace elements test of the Middle Ordovician YiJianfang Formation fracture-cave fillings in Fuman area of Tarim Basin, and the standardization of the measured rare earth elements in North American shale, it is found that the overall curve shows a rightward trend, the Ce shows a weak deficit, and the Eu shows a strong positive anomaly. The Sr, Al and Ti elements showed that the fillings were affected by terrigenous detritus disturbance, and the Sr/Ba was generally low and all were less than 1. It was inferred that the fillings were from freshwater environment. The Fe/Ti, Al/(Al+Fe+Mn), Cu+Pb+Zn and Fe+Mn/Ti values indicated that the fillings were less affected by hydrothermal activity. The ratios of U/Th, Ni/Co and V/Cr suggested that the filling was formed in the oxidized environment. The comprehensive study shows that the fillings of the middle Ordovician Yijianfang Formation are mainly formed in the atmospheric fresh water environment under oxidized conditions, and are mainly disturbed by terriglogenic materials and less affected by deep hydrothermal solution.