Writers found some important fossil of Helenifore robustum and Helenifore laticlavium radiolarian fauna from the bedded chert of the Liujiang Formation, which distributed abroad in southeastern Yunnan province, so the chert is Frasnian of Late Devonian. The chert has SiO280.2%~95.72%, Al2O30.32%~3.83%, average is 2.07%, Si/Al ratio is 20.94~62.16, which indicates that the chert is riched in terrigenous muddy deposit.Most of Mn/TiO2 ratios of the chert are 0.03~0.41, but sample 6PB5 is 0.34. All Si/(Si+Al+Fe) ratios are greater than 0.9, whichsuggests that the chert formation is mainly controlled by biological action and terrigenous deposit, and the hydrothermal activity is feebleness. The Ce/Ce* ratios are 0.62~1.37, there is Ce/Ce* negative individually. LaN/YbN ratios are 0.47~1.74, average value is 1.21. LaN/CeN ratios are 0.75~1.70, average value is 111. The chert has geochemical characteristics of continental edge chert, minority has characteristics of abyss. The V contents are mainly 14.5~30.9μg/g, showing the characteristics of continental edge chert; and a few are as high as 75.3μg/g and 218μg/g, might be related to hydrothermal action. U/Th ratios are mainly between 0.27 and 0.40, average is 0.86, three samples have high U/Th ratios greater than 1.0, indicating that the chert is mainly natural biogenetic, parts are strongly affected by hydrothermal action. The radiolarian bedded chert, its geochemical characteristics and turbidite formation indicate that southeastern Yunnan area is a continental marginal rift basin at Frasnian, Late Devonian.