Two types of heterogeneous extinction phenomena are observed in the olivine and pyroxene crystals of a mantle-derived lherzolite xenolith from Hannuoba, Hebei Province. The laser Raman microprobic analysis indicates that, in olivine exhibiting a heterogeneous extinction character with obvious boundary, the Raman bands belonging to different symmetric species appear regularly in the spectra in different extinction zones. It is proved that there exists a sudden torsion of crystal axes along the boundary between the extinction zones. In pyroxene displaying an undulatory extinction character, the relative intensities of the Raman bands measured from neighboring points show a gradual change. It is demonstrated that the torsion of crystal axes in pyroxene lattice takes place progressively. Three deductions could be drawn from the experiments; 1. High-temperature (>1000Cº)creep strain in the upper mantle could not result in phase transition in these olivine and pyroxene crystals. 2. The two heterogeneous extinction phenomena are all torsions of crys- tal axes in essence, but the torsion units are different in size. In olivine, the size is in micrometer with thousands of unit cells included. In pyroxene, it is in sub-unit cell level. 3. Under the same pressure-temperature conditions, the type of the torsion of crystal axes occurring in a crystal lattice mainly depends on the structural character of the crystal itself.