Biodegradable copolyester and method for preparing the same

There is disclosed a biodegradable copolyester having a combination structure consisting of one or more repeating unit of alkyleneterephthalate and one or more repeating unit of hydroxyalkanoate, represented by the following general formula I: см. иллюстрацию в PDF-документе wherein n is an integer not more than 10, R is --CH3 or --C2 H5,5, X is, см. иллюстрацию в PDF-документе and a, b and c are independently a natural number, along with a preparation method therefor. An aromatic polyester have repeating unit of alkyleneterephthalate is reacted with an aliphatic polyester having repeating unit of hydroxyalkanoate at 100° C. or more in a proper solvent, such as nitrobenzene and dimethylsulfoxide, in the presence of a catalyst, such as dibutyltin oxide, tin[IV] chloride, tin[IV] octoate, hexabutyl distannoxane, tributyltin methoxide, or tributyltin chloride. It is superior in biodegradability and can be produced in low cost.