Disclosed is a bio-based polycarbonate ester comprising: (i) repeat unit 1 obtained from a condensation reaction of 1,4:3,6-dianhydrohexitol and carbonate; and (ii) repeat unit 2 obtained from a condensation reaction of 1,4:3,6-dianhydrohexitol and 1,4-cyclohexanedicarboxylate; and a preparation method for the bio-based polycarbonate ester, comprising the steps of: (1) preparing a compound 1,4-diphenyl-cyclohexanedicarboxylate through a trans-esterification or esterification reaction of a compound represented by formula 2 and phenol; and (2) preparing a compound comprising a repeat unit represented by formula 1 through a polycarbonate melt polycondensation reaction of the 1,4-diphenyl-cyclohexanedicarboxylate prepared in step (1), a compound represented by formula 4 and 1,4:3,6-dianhydrohexitol.