The invention discloses a poly(butylene succinate) which is prepared by copolymerizing succinic acid, butylene glycol and cyclic dibasic alcohol. The poly(butylene succinate) comprises succinic acid residue, butylene glycol residue and cyclic diol residue, wherein the butylene glycol residue accounts for 90-98% of the total dibasic alcohol, and the cyclic diol residue accounts for 2-10% of the total dibasic alcohol. The preparation method comprises the following steps: reacting succinic acid, butylene glycol and cyclic dibasic alcohol at 200-230 DEG C under the action of a catalyst to perform direct esterification, thereby obtaining an esterified substance; adding a stabilizer, and carrying out pre-polycondensation reaction at 220-250 DEG C to obtain a prepolymer; carrying out polycondensation reaction on the prepolymer at 235-250 DEG C while gradually reducing the vacuum degree of the reaction system to less than 150Pa; and after the polycondensation finishes, adding carbodiimide compounds into the reaction product, and mixing for 2-15 minutes, thereby obtaining the poly(butylene succinate). The polyester synthesized by the method disclosed by the invention has the advantages of high heat resistance, high melting point, controllable degradation rate, excellent mechanical properties and excellent processability.