A method for preparing a cyclopeptide, comprising the following steps: (A) providing compounds represented by the following formulas (II-1) or (II'-1) and (II-2), R c -NH-R 1 -COOH (II-2) wherein, each of R a and R b independently is alkyl, cycloalkyl, aryl or heteroaryl; R c is a protection group; G is H or OC(CH 3 ) 3 ; and R 1 is in which each of R 2 and R 3 independently is H or C 1-6 alkyl; X is O, S, CH 2 or N-R 4 , in which R 4 is H, C 1-6 alkyl, (CH 2 CH 2 O) n H, ―C(=O)-C 1-10 alkyl, or C(=O)(C 2 H 4 ) 2 C(=O)O(C 2 H 4 O) n H,in which n = 1-3; (B) performing a reaction between the compounds of formulas (II-1) or (II'-1) and (II-2), to obtain a compound represented by the following formula (II-3) and (II' -3), respectively, (C) performing a reaction between the compound of formula (II-3) or (II'-3) and a compound represented by the following formula (II-4) or (II'-4), respectively, to obtain a compound represented by the following formula (II-5), and (II'-5), respectively. each of R d and R e independently is a protection group; and (D) performing a cyclization reaction of the compound of formula (II-5) or (II'-5) with a catalyst, to obtain a compound represented by the following formula (I) or (I'), respectively, wherein G' is H or OH; the catalyst is MoO 2 Cl 2 , V(O)OCl 2 , V(O)(OAc) 2 , V(O)(O 2 CCF 3 ) 2 , Nb(O)Cl 2 , MoO 2 (acac) 2 , V(O)(OTs) 2 , VO(OTf) 2 or V(O)(NTf 2 ) 2 . (A) providing compounds represented by the following formulas (II-1) or (II'-1) and (II-2), R c -NH-R 1 -COOH (II-2) wherein, each of R a and R b independently is alkyl, cycloalkyl, aryl or heteroaryl; R c is a protection group; G is H or OC(CH 3 ) 3 ; and R 1 is in which each of R 2 and R 3 independently is H or C 1-6 alkyl; X is O, S, CH 2 or N-R 4 , in which R 4 is H, C 1-6 alkyl, (CH 2 CH 2 O) n H, ―C(=O)-C 1-10 alkyl, or C(=O)(C 2 H 4 ) 2 C(=O)O(C 2 H 4 O) n H,in which n = 1-3; wherein, each of R a and R b independently is alkyl, cycloalkyl, aryl or heteroaryl; R c is a protection group; G is H or OC(CH 3 ) 3 ; and R 1 is in which each of R 2 and R 3 independently is H or C 1-6 alkyl; X is O, S, CH 2 or N-R 4 , in which R 4 is H, C 1-6 alkyl, (CH 2 CH 2 O) n H, ―C(=O)-C 1-10 alkyl, or C(=O)(C 2 H 4 ) 2 C(=O)O(C 2 H 4 O) n H,in which n = 1-3; (B) performing a reaction between the compounds of formulas (II-1) or (II'-1) and (II-2), to obtain a compound represented by the following formula (II-3) and (II' -3), respectively, (C) performing a reaction between the compound of formula (II-3) or (II'-3) and a compound represented by the following formula (II-4) or (II'-4), respectively, to obtain a compound represented by the following formula (II-5), and (II'-5), respectively. each of R d and R e independently is a protection group; and (D) performing a cyclization reaction of the compound of formula (II-5) or (II'-5) with a catalyst, to obtain a compound represented by the following formula (I) or (I'), respectively, wherein G' is H or OH; the catalyst is MoO 2 Cl 2 , V(O)OCl 2 , V(O)(OAc) 2 , V(O)(O 2 CCF 3 ) 2 , Nb(O)Cl 2 , MoO 2 (acac) 2 , V(O)(OTs) 2 , VO(OTf) 2 or V(O)(NTf 2 ) 2 . wherein G' is H or OH; the catalyst is MoO 2 Cl 2 , V(O)OCl 2 , V(O)(OAc) 2 , V(O)(O 2 CCF 3 ) 2 , Nb(O)Cl 2 , MoO 2 (acac) 2 , V(O)(OTs) 2 , VO(OTf) 2 or V(O)(NTf 2 ) 2 . <EOS>