The Manketouebo formation widely distributing in Manzhouli- Xinbaerhuyouqi area in the west of Daxinganling mountains is lack of system paleontology and chronology research, which lead to a controversy of its forming age and uncertain climate in its forming age.Through field geological investigation, Nestoria fossil and Cedripites- Piceaepollenites- Psophosphaera fossil assemblage is found in the Manketouebo formantion. and they lived in the late stage of the late Jurassic epoch. They also reflect it was a subtropical and semi- humid to humid climate in their living age. The zircon U- Pb age of the rhyolite in the upper part of Manketouebo formation is 156.61±0.96Ma, Combined with paleontology chronology result, It is determined that the Manketouebo formation was formed in the middle and late stage of the late Jurassic epoch. On the other hand, The zircon U- Pb age of the rhyolite(156.61±0.96Ma) also indicates that the time limit of the fossil zone, represented by Nestoria, is the Kimmeridgian.