Through the survey of 581.64 km road-cut sections and the study 20.16 km measured section, five volcanic eruption cycles (I, Ⅱ, Ⅲ, Ⅳ, Ⅴ) have been recognized in the Yixian Formation in the Fuxin area of western Liaoning Province. The lower part of each eruption cycle is characterized by explosion facies with volcanic clastic rocks, and the upper part of each cycle consists of lava facies. The main types of lava include basalt, basaltic andesite, andesite, dacite, liparite, obsidian, and trachyandensite. In each eruption cycle or alkaline volcanic rocks appear to become more abundant up section.