Abstract: The basalt of Woniusi Formation is distributed extensively in Shidian area, Yunnan Province. It was thought previously that this basalt belonged to explosive littoral-neritic facies. During the field work in recent years, the authors found that sedimentary intercalations are missing in basalt of Woniusi Formation. And that the basalt is similar to Emei Shan basalts in petrology and geochemistry and has some characteristics of terrestrial extrusive facies.