The invention discloses a purification method of 
semaglutide. The method comprises the following steps: (1) dissolving a crude 
semaglutide product in dilute 
ammonia water, carrying out water bath andfiltering successively, and collecting a filtrate; (2) performing 
gradient elution by taking a reverse-phase 
silica gel filler as a 
stationary phase, a 
salt solution with a pH value regulated to 7-9 by 
ammonia water as a mobile phase A and 
acetonitrile as a mobile phase B, collecting fractions, and performing rotary 
evaporation to remove a part of the 
solvent to obtain a primarily-purified solution; (3) carrying out 
gradient elution by taking the reversed-phase 
silica gel filler as the 
stationary phase, a 
saline solution with a pH value adjusted to 2-3 by 
phosphoric acid as the mobile phase Aand a 
mixed solution of 
acetonitrile and isopropanol as the mobile phase B, collecting fractions, and carrying out rotary 
evaporation to remove a part of the solvents so as to obtain a secondarily-purified solution; and (4) carrying out 
gradient elution by taking the reverse-phase 
silica gel filler as the 
stationary phase, an 
aqueous solution of 
ammonium bicarbonate as the mobile phase A and 
acetonitrile as the mobile phase B, collecting fractions, carrying out rotary 
evaporation, and carrying out freeze-
drying so as to obtain saltless refined 
peptide of 
semaglutide, wherein the saltless refined 
peptide has purity of greater than 99.5% and an individual 
impurity content of less than 0.1%. The method is simple and convenient to operate and facilitates large-scale preparation of semaglutide.