S)-1-fluorenylmethoxycarbonyl-4-azido-L-proline,a very important pharmaceutical intermediate for the synthesis of peptide drugs,was synthesized from(4R)-1-(tert-butoxycarbonyl)-4-hydroxy-L-proline ethyl ester via mesylation,azide displacement,hydrolysis and deprotected,followed by condensation with 9-fluorenylmethyl succinimidyl carbonate in an overall yield of 62.