NOVELTY - Solid phase synthesis of degarelix involves dissolving amino acid ivDde-OH and Fmoc-(4-aminophenyl)acetic acid in anhydrous ethanol, adding trifluoroacetic acid, refluxing; using Fmoc solid phase synthesis method, coupling Fmoc-D-Ala-OH, Fmoc-Pro-OH, Fmoc-L-Lys(Boc)-OH, Fmoc-Leu-OH with Fmoc-4-Aph(ivDde)-OH, Fmoc-Ser(tBu)-OH, Fmoc-3-(3-pyridyl)-D-Alanine, Fmoc-D-Phe(4Cl)-OH, Fmoc-3-(2-naphthyl)-D-alanine, connecting to amino group of amino acid resin to form Fmoc-decapeptide resin; deprotecting, forming Ac-decapeptide resin, deprotecting, connecting orotic acid to C-terminal and cleaving.    USE - For solid phase synthesis of degarelix (claimed) used as GnRH receptor antagonist for treating advanced prostate cancer.    ADVANTAGE - The method avoids side reaction, is simple and is easy to control, is safe for human body and environment, provides high yield of product, and is suitable for large scale production. The method is simple, provides product in high yield, avoids series of problems associated with Boc solid phase synthesis method, avoids the use of HF gas, reduces environmental pollution and does not cause damage to human body, requires mild reaction conditions, and is easy to control.    DETAILED DESCRIPTION - A solid phase synthesis method of degarelix involves dissolving amino acid ivDde-OH and Fmoc-(4-aminophenyl)acetic acid (Fmoc-4-Aph-OH) in anhydrous ethanol, adding trifluoroacetic acid, refluxing and forming Fmoc-4-Aph(ivDde)-OH; using Fmoc solid phase synthesis method, sequentially coupling the Fmoc-D-Ala-OH, Fmoc-Pro-OH, Fmoc-L-Lys(Boc)-OH, Fmoc-Leu-OH, and Fmoc-D-4-Aph(X)-OH with Fmoc-4-Aph(ivDde)-OH, Fmoc-Ser(tBu)-OH, Fmoc-3-(3-pyridyl)-D-Alanine (Fmoc-D-3Pal-OH), Fmoc-D-Phe(4Cl)-OH, and Fmoc-3-(2-naphthyl)-D-alanine (Fmoc-D-2Nal-OH) using coupling agent, connecting degarelix to amino group of amino acid resin to form Fmoc-decapeptide resin i.e. Fmoc-D-2Nal-D-Phe(4-Cl)-D-3Pal-Ser(tBu)-4-Aph(ivDde)-D-4-Aph(X)-Leu-L-Lys(Boc)-Pro-D-Ala-amino acid resin; taking the decapeptide resin and removing Fmoc protection, and then preparing N-terminal acetylated amino acid resin i.e. Ac-decapeptide resin i.e. Ac-D-2Nal-D-Phe(4Cl)-D-3Pal-Ser(tBu)-4-Aph(ivDde)-D-4-Aph(X)-Leu-L-Lys(Boc)-Pro-D-Ala-amino acid resin; taking the Ac-decapeptide resin and removing protecting group, and then connecting orotic acid to C-terminal of amino acid resin using coupling agent, and conducting cleavage of peptide resin to form crude degarelix.    X=OH protecting group or t-Bu protecting group.