There are two kinds of spinels in a granulite terrain of Yushujgou, South Tianshan Mountain. One occurs in the intermediate and basic granulite units and is characterized by enriched Al and poor Cr, belonging to Al-spinel. In thin sections it shows dark green color and subhedral to anhedral form, and coexists with other metamorphic minerals, suggesting a neogenic metamorphic mineral of granulite facies. The other occurs in the adjacent ultramafic rock unit, belonging to Cr_spinel. In thin sections, it is dark brown in color and is scattered among olivine, clinopyroxene and orthopyroxene as irregular grains, indicating a stable residual mineral in the process of granulite facies metamorphism. The spinel in the ultramafic rock unit belongs to I-type spinel, as proposed by Dick et al . This implies that the ultramafic rock is a part of oceanic lithosphere mantle. Characteristics of these two kinds of spinels not only indicate that the whole terrain underwent granulite facies metamorphism but also provide direct mineralogical evidence for the argument that Yushugou ophiolite suite of granulite facies lies in an environment of oceanic basin.