This paper reports the oxygen isotope data of metamorphic minerals. in the Chencai Group and the determination of their metamorphic temperatures using these data. Two rock samples were collected from the Dingjiawu .strata profile in the Chencai Group, Zhuji: Pure quartz, magnetite and garnet were separated from the samples. The BrPs technique was used in extracting oxygen from these minerals. Oxygen reacted with graphite to generate CO2, and then the oxygen isotope ratio was measured on ME1T-250 model mass spectrometer. The Δ18O values of two quarts-magnetite pairs calculated in the samples were, yielding temperatures of 554 and 573℃，respectively, which is geologically rea- sonable. In contrast, the temperature calculated from quartz-garnet pair was high anomaly of 623℃，indicating that oxygen isotopes are not in equilibrium between two minerals. Thus, the average temperature of 565士10℃，calcula ted from two quartz-magnetite pairs, is selected as metamorphic temperature of rocks in the Chencai strata. Oxygen isotope thermometry, therefore, is one of the available techniques for the determination of temperatures of metamorphic rocks.