The matrix texture and minerals of seafloor basalt have been studied by using E lectron Probe Microanalyzers (EPMA) in this paper. The matrix texture is glassy on the chilled border, and crystalline in the interior. The groundmass has the same mineral components as phenocryst, and is composed of plagioclase, augite and olivine. A s c ompared with phenocrystal minerals, the matrix plagioclase is poor in Ca and ric h in Na, and the matrix augite and olivine are poor in Mg and rich in Fe.