Abstract:The exposed area of the Panzhihua basic intrusion is about 38 kmz,I9km long and 2km wide. The layered structure in the intrusion is well developed. The intrusion body has K-Ar and U-Pb age of 306-320Ma and it can be divided into 4 zones from bottom to top. The main rocks of zone I are fine-grained olivine- gabbro, titanomagnetite rock and coarse-grained pegmatitic gabbro; those of zone II include titanomagnetite-gabbro and gabbro; the main rock of zone III are gabbro and anorthosite and zone MY is composed of amphibole gabbro. Samples that were studied by oxygen isotope analysis are from zones I-IV. The whole rock δ180 values for 6 samples are+6.27-+s6。91%,and for the other 2 samples- +8. 99- +9.19%,for 20 of 23 titanomagnetite samples δ18O values range from +0.55 to+3.46%, and for the other 3 samples - from +4.11 to +4.86%;for 12 of 21 plagioclase samples from +6.18 to +7.60%,and for the other 9 samples- +8.12 to +11.99%.One ilmenite sample has a δ180 value of +4. 56%.According to the oxygen isotope determination results it is suggested that the primary magma of the Panzhihua intrusion probably originated from the upper mantle. The ⊿δ18o values of the oxygen isotope fractionation between coexisting pla- gioclase and titanomagnetite for zone I are 5.03-9.46 and the oxygen isotope equilibrium temperature ranges from 455 to 730.For zones II, III, and IV the ⊿δ180 values of oxygen isotope fractionation are 2.87-3.94, 4.93-5.85, and 3. 87-6.19, respectively. While their oxygen isotope equilibrium temperatures are 871º-1045℃,650º-740℃and 621º-871℃,respectively.