Disclosed is a biodegradable polyester composition, comprising the following components: a, a biodegradable aliphatic-aromatic polyester; and b, an alkali metal element, wherein the alkali metal element is selected from at least one of potassium element and sodium element; and the weight content of the alkali metal element is 1 ppm - 232 ppm based on the total weight of the biodegradable polyester composition. In the present invention, by adding an alkali metal salt in the biodegradable polyester composition and controlling the content of the alkali metal element in the composition within the range of 1 ppm - 232 ppm, the static friction coefficient of a film material can be improved, and the static friction coefficient of the film material is controlled within the range of 0.2 - 0.3 to make the film easier to open and simultaneously reduce the friction between the film and equipment, so as to ensure the smooth performance of film-blowing.