Abstract: The Middle Devonian of Wuding, Yunnan shows a continous sedimentary Series about 400m thick with the underlying Lower Devonian, and may be subdivided into three parts based on the fossils. The lower part consists of pale sandstone interbeded with black shale, yielding Wudinolepis and Arthrodira fossils. The middle part consists of yellow sandstone intercalated with mar lite yielding very abundant antiarchians, Bothriolepis, Dianolepis liui and Xichonolepis etc. The upper part consists chiefly of light brown sandstone yielding Xichonolepis as well as plant fossils and is overlaid by the Jurassic rocks. The Devonian fish fossils and stratigraphy of Wuding have been studied by many palaeontologists since 1942. Prof. H. C. Wang for the first time reported Bothriolepis fossils from Wuding. In 1965, Zhang Guorui described Wudinolepis weni, Dianolepis liui and Bothriolepis tungseni. The horizons of the fish-bearing strata were considered as Middle Devonian. In 1973, Liu Yuhai and Wang Junqing in "Some problems on the Devonian stratigraphy of eastern Yunnan" discussed the division of Devonian System of Wuding as shown in the table l. Zhao Xiukun's "The Devonian System of Wuding region" discussed again the division of Wuding Devonian System (Table 1) in 1978. Wang (1984) described some Arthrodira fossils from marl intercalated bed of black shale yielding Wudinolepis, and considered them as Eifelian in age. During recent excavations in Wuding region, a few new fish fossils have been discovered. Especially singnificantone is the discovery of a new antiarchian associated with Wudinolepis and other small antiarchians. Another new discovery is Wudinolepis found in Luquan. The fossils were preserved together with Arthrodira fragments as Wuding. It appears that Wudinolepis and other smell antiarchians should represent an assemblage of Eifelian. Bothriolepis—Dianolepis ligi represent a stable assemblage of early Givetian in China. Therefore the middle part including Bothriolepis—Dianolepis liui fauna is corresponding to the Haikou Formation of Kunming or Tiaomajian Formation of Hunan. The upper part yielding Xichonolepis and plant fossils should correspond with Qujing Formation, because the corresponding horizons near Wuding yield Stringocephalus and Emanuella etc. Based on the fact mentioned above, the upper, middle and lower parts should be represented by the Sujiapo, Haikou and Jiucheng Formations respectively. A new proposition about the division of the Devonian System of Wuding region has been made and shown in table 1.