The invention discloses a method for synthesizing an AHU377 calcium salt. The method comprises the following steps: reacting 4-bromo-D-phenylalanine with thionyl chloride, reacting obtained methyl 4-bromo-D-phenylalaninate hydrochloride with BOC acid anhydride, reacting the obtained reaction product with phenylmagnesium bromide to obtain N-tert-butyloxycarbonyl-amino-4,4-biphenyl-R-alanine methylester, reacting the N-tert-butyloxycarbonyl-amino-4,4-biphenyl-R-alanine methyl ester with sodium borohydride, reacting the obtained reaction product with ethyl 2-(triphenylphosphoranylidene)propionate to obtain ethyl (4R)-5-[1,1'-biphenyl]-4-yl-4-[[tert-butoxycarbonyl]amino]-2-methyl-2-pentenoate, reacting the ethyl (4R)-5-[1,1'-biphenyl]-4-yl-4-[[tert-butoxycarbonyl]amino]-2-methyl-2-pentenoatewith lithium hydroxide, performing catalytic hydrogenation, reacting the obtained catalytic hydrogenation product with thionyl chloride to obtain ethyl (2R, 4S)-5- ([1,1-biphenyl)-4-amino-2-methylpentenoate hydrochloride, and stirring and reacting the ethyl (2R, 4S)-5- ([1,1-biphenyl)-4-amino-2-methylpentenoate hydrochloride, calcium chloride and succinic anhydride to obtain the target product.The method has the advantages of simple steps, mild reaction conditions, high purity and high yield.