A heat-resistant, bio-based polycarbonate ester prepared by melt polycondensation of 1,4:3,6-dianhydrohexitol and a carbonate, 1,4-cyclohexanedicarboxylate, or a terephthalate is disclosed. The heat-resistant, bio-based polycarbonate ester includes a repeat unit 1 of Formula 1, a repeat unit 2 of Formula 2, and a repeat unit 3 of Formula 3: The polycarbonate ester has excellent heat resistance, transparency, and processability. A method of producing the polycarbonate includes a step of melt polycondensation of 1,4:3,6-dianhydrohexitol and a carbonate, 1,4-cyclohexanedicarboxylate, or a terephthalate.