Located in the northeast of Olongbuluck block on the northern margin of Qaidam Basin, the Hongliugoubei mafic-ultramafic intrusion is composed of harzburgite, olivine websterite, plagioclase-bearing clinopyroxene peridotite, olivine gabbro-norite, melaolivine-gabbro, norite and gabbro and belongs to a dike-shaped intrusion, with an exposed area of about 0.1 km². Various lithofacie belts show gradual transition relationship. Electron microprobe analyses show that the rock-forming minerals are composed of chrysolite, augite and plagioclase and their crystallization temperatures vary between 1 307 and 1 122℃. The intrusion is characterized by obvious mineralization of ilmenite, with main ore minerals being ilmenite, titanomagnetite and magnetite. The inversion of primary magma composition based on the compositions of most Fo-rich olivines indicates that the parental magma of Hongliugoubei intrusion belonged to common basalt magma containing about 8.49% MgO, 10.03% FeO and 1.63% TiO₂. Studies of temperature and oxygen fugacity conditions of rock-forming minerals reveal that oxygen fugacity of magma gradually increased from olive crystallization to augite crystallization and this seems to be the main factor that controlled the crystallization of Ti-Fe oxide.