Biodegradable polyester composition

The invention discloses a biodegradable polyester composition. On the basis of the total weight of the biodegradable polyester composition, the weight content of annular compound ester of the structure as shown in formula (I) (please see the formula in the specification) is 100-950 ppm. On the basis of the total weight of the biodegradable polyester composition, the weight content of cyclopentanone is 0.5-85 ppm. By adding annular compound ester and cyclopentanone in the composition, the content of annular compound ester and cyclopentanone in the composition is controlled to be within a certain range, the heat and oxygen aging resistance of the biodegradable polyester composition can be greatly improved, a film obtained through blow molding or a workpiece obtained through injection molding is boiled for 240 h through 95% ethyl alcohol at the temperature of 40 DEG C, surface precipitate is little, excellent surface appearance performance is achieved, the lubrication degree of the film can be improved in the blow molding process of the biodegradable polyester composition, the film blowing speed is 176 Kg/h, the film thickness difference is smaller than 0.2 micron, the film thickness relative deviation is smaller than 1%, and stability of film bubbles and film blowing continuity are guaranteed.