The present paper studies the oxygen isotope in coexisting minerals of regionally metamorphosed rocks from Zhuozi-Yanggao area with discussion of related metamorphic temperature, 80'8 values or metamorphic water in equlil- brium with quartz and magnetite as well as variations of the δ18 values of some minerals. The widely distrubuted Archaean rocks exposed in this area are Jining group with the metamorphic grade of granulite facies. The metamorphic rocks in this area can be divided into khondalite suite and granulite suite. The asse- mblages of their minerals can be summarised as follows: (a)khondalit suite:quartz + perthite + garnet+biotite士plagioclase士silli- manite土spine + opaq ue oxide. (b)granulite suite:hyperthene+plagioclase士quartz士clinopyroxenes士hor- nblende士biotite+opaque oxied. The δ18 of coexisting minerals from a mumber of regionally metamorpho- sed rocks have been measured, using a bromine pertafluoride technique. Accor- ding to their increasing tondenc y to concentrate δ18, the minerals sequence is magnetite, pyroxene, plagioclase, garnet and quartz. The formation tempera- ture of the granulite facies has been determined on the basis of the difference in δ18 values between the quartz and mageetite, pyroxene and magnetite as well as quartz and garnet mineral pairs. The temperature ranges from 500℃ to 882 ℃.Some formation temperatures of the granulite facies are lower than that usually expected. It may be explained by the retrogresie metamorphic effect which has been supported by rock investigetion. Judging from the data of oxygen isotopesanalysis it appears that the δ18 values of quartz tend to decrease distinctly as the metamorphic grade increa- ses in this area. The δ18 values of quartz for granulite faciess increased becau- se of the effect of migmatization.