The corundum megacrysts in basalts from Changle of Shandong Province, as the main source of blue sapphires in China, contain varied types of fluid and melt inclusions. Knowledge of their micro-thermometry, compositions, densities, and trapping temperatures (T) and pressures (P) is insufficiently known, which has hindered the study of source areas of sapphires, phase behaviors of fluids/ melts in the Earth's interior, and genesis of corundum megacrysts. The authors performed detailed mirco-thermometric measurement of the inclusions and used a newly-developed technique to analyze the densities of some fluid inclusions that were hardly obtained from micro-thermometry. Fluid inclusions are CO2-rich with minor other volatiles and have lower densities of 0～0.55 g/cm3（mostly lower than 0.3g/cm3）or otherwise higher densities of 0.65～0.75 g/cm3. The fluid inclusions with lower densities resulted from leakage. The other type of fluid inclusions is rich in H2O-CO2 with minor other volatiles and has low salinities with bulk densities of 0.64～0.78 g/cm3. Except for a few which can be homogenized at 1100～1300℃, the two types of melt inclusions mostly cannot realize whole homogenization, which is attributed to the high viscidity of solid materials within the inclusions. For the other three types of melt inclusions, except for some which can be homogenized at 1040～1280℃, the others cannot be homogenized due to heterogeneous trapping of immiscible fluids and melts. Consequently, the lowest homogeneous temperatures of 1000～1100℃ are considered to be the real trapping temperatures. On the basis of the temperatures and by using isochores of fluid inclusions, the trapping pressures are constrained at 350～640 MPa, corresponding to 12～23 km litho-static pressures of the lower/middle crust. The phase changes in many CO2-rich inclusions cannot be observed during heating and cooling, which seems to be an important symbol for distinguishing Changle corundum from corundums of other areas. In addition, the heterogeneous trapping and the coexistence of CO2-rich/CO2-H2O-rich inclusions and melt inclusions suggest that immiscibility between fluids and melts occurred under the trapping T-P conditions. It is thus concluded that the Changle corundums crystallized from a CO2-oversaturated melts with high temperatures in the lower/middle curst.