Polycarbonate（PC）was prepared by transesterification between bisphenol-A（BPA）and diphenyl carbonate（DPC）in supercritical carbon dioxide（ScCO2）.In the process，phenol formed from the reaction was dissolved and diffused into ScCO2 phase.The structure of the synthesized product was characterized by FT-IR and 1H-NMR.The results of GPC show that there are two different reaction mechanisms，linear condensation and cyclic reaction in the synthesis process，and the molecular weight（MW）reaches 1.17×105 and Pd is 1.33.The DSC curves show that supercritical carbon dioxide can plasticize PC so that the Tg of PC decreased.Under the pressure of 10 MPa，the effects of reaction time，rotary speed of the propeller and reaction temperature on PC molecular weight were investigated.The optimal operation conditions are reaction time of 50 h，rotary speed of 800 r·min-1，reaction temperature of 120℃，respectively.