Abstract: The peridotitic komatiites in Jifeng area of Daxinganling are with fine microspinifex texture.The matrix materials existing between olivine and augite crystals indicate a volcanic origin.Systematic research has initialy iden-tified a chill zone and a spinifex zone,which constitute an incomplete condensate unit.The petrochemical characteristics of the Jifeng komatiites are in accordance with the peridotitic komatiites in South Africa and Western Australia.The geochemistry study shows a close genetic relationship between the komatiites and the associated basalts,with a positive correlation,conforming to the evolutionary trend of komatiite-tholeiite.The cardinal elements,trace elements and REE of the komatiites in the area present a perfect attribute of type Ⅱ komatiite,which is compatible with the type Ⅱ komatiite in South Africa,India,and West Greenland.The Jifeng komatiites are characterized by low LREE affluence,withε_Nd (T)=+7.51,showing that the komatiites are derived from partially melted depleted mantle.The komatiites were formed in Mesoproterozoic,in atectonic environment of tensile crust,while the rising komatiite magma was quenched and rapidly cooled.The Jifeng komatiites provide a new key for research of Mesoprote rozoic tectonics in Daxinganling area.