Disclosed are a biodegradable polyester and the use thereof, said biodegradable polyester comprising: A) an acid component comprising the following repeating units: 40-48 mol% of terephthalic acid A1; 38.5-50 mol% of sebacic acid A2; and 2-20 mol% of aliphatic dibasic acid A3 having a carbon chain length with less than or equal to 6 carbons; and B) a butanediol. With a low content of terephthalic acid, the introduction of the aliphatic dibasic acid monomer having a carbon chain length with less than or equal to 6 carbons sensibly improves the mechanical property of the material, specifically, when storing the material in a humid environment so as to maintain the good mechanical property retention rate.