The invention relates to a method for synthesizing polyester with dibasic acid or dibasic acid anhydride or dibasic acid ester and dibasic alcohol. The method comprises the steps of synthesizing the dibasic acid or dibasic acid anhydride or dibasic acid ester and dibasic alcohol bulks into an oligoester, and then carrying out polycondensation to the loligoester in ionic liquid. The method realizes excellent effects of increasing molecular weight of the polyester, cycle using of reaction medium ionic liquid, reducing energy consumption as well as shortening reaction time. The invention also relates to the polyester products obtained by the method of the invention.