The invention discloses a method for synthesizing biapenem medicine intermediates. The method has the advantages that the biapenem medicine intermediates 4-AA are prepared from (R)-3-polyhydroxybutyrate which is a raw material, and the raw material in the routes is inexpensive, is easily available and can be substantially purchased; the method includes simple steps, the various steps are high in yield, and reaction is simple; chiral reagents and chiral resolution are omitted, accordingly, the method is low in cost and high in yield, and reaction conditions are easily available.