Abstract:The volcanic rocks of Meifeng formation in Lesser khingan mountains are widely exposed, which is of great significance to study the geochemical characteristics of the volcanic rocks of Meifeng formation. This paper makes research on the petrographic, geochemical and chronological characteristics of the volcanic rocks of Meifeng formation in Sunwu area of Lesser khingan mountains, and discusses their formation age, petrogenesis and tectonic environment. Zircon U- Pb results show that the Meifeng formation was formed in the early Cretaceous (105. 2 ± 0. 5 Ma). Meifeng formation is dominated by basic volcanic rocks, belonging to high potassium calc alkaline series. Enrichment of Rb, Ba, th, u, La, CE, relative loss of Nb, Ti and other elements; δEu = 0. 71 ~ 0. 94, light rare earth is slightly enriched, heavy rare earth fractionation is not obvious. The above rock geochemical characteristics show that the original magma of the volcanic rocks of Meifeng formation originated from the mantle and was modified by the contamination of crustal materials. The volcanic rocks of Meifeng formation in the study area were formed in an extensional environment and were the product of the ancient Pacific plate’s subduction to the Asian continental plate.