A method for measuring a polymer modification ratio, comprising: preparing a first solution by dissolving a polymer mixture containing a modified polymer and an unmodified polymer in a first solvent; injecting the first solution into a column filled with an adsorbent; adsorbing the modified polymer onto the adsorbent, and eluting the first solution in which the unmodified polymer is dissolved; transferring the eluted first solution to a detector; injecting a second solvent into the column to elute a second solution in which the adsorbed modified polymer is dissolved; and transferring the eluted second solution to the detector, wherein the modification ratio is calculated by Equation 2 below from a chromatogram according to the method for measuring a polymer modification ratio; Modification ratio % = Peak area of modified polymer Peak area of unmodified polymer + Peak area of modified polymer × 100 where the peak area of the unmodified polymer is a peak area of the chromatogram for the first solution transferred to the detector, and the peak area of the modified polymer is a peak area of the chromatogram for the second solution transferred to the detector; and the second solvent is injected after the entire amount of the unmodified polymer is eluted wherein the point in time when the entire amount of unmodified polymer is eluted is indicated by a point in time when the signal of the unmodified polymer is no longer detected from the detector. preparing a first solution by dissolving a polymer mixture containing a modified polymer and an unmodified polymer in a first solvent; injecting the first solution into a column filled with an adsorbent; adsorbing the modified polymer onto the adsorbent, and eluting the first solution in which the unmodified polymer is dissolved; transferring the eluted first solution to a detector; injecting a second solvent into the column to elute a second solution in which the adsorbed modified polymer is dissolved; and transferring the eluted second solution to the detector, wherein the modification ratio is calculated by Equation 2 below from a chromatogram according to the method for measuring a polymer modification ratio; Modification ratio % = Peak area of modified polymer Peak area of unmodified polymer + Peak area of modified polymer × 100 where the peak area of the unmodified polymer is a peak area of the chromatogram for the first solution transferred to the detector, and the peak area of the modified polymer is a peak area of the chromatogram for the second solution transferred to the detector; and the second solvent is injected after the entire amount of the unmodified polymer is eluted wherein the point in time when the entire amount of unmodified polymer is eluted is indicated by a point in time when the signal of the unmodified polymer is no longer detected from the detector. where the peak area of the unmodified polymer is a peak area of the chromatogram for the first solution transferred to the detector, and the peak area of the modified polymer is a peak area of the chromatogram for the second solution transferred to the detector; and the second solvent is injected after the entire amount of the unmodified polymer is eluted wherein the point in time when the entire amount of unmodified polymer is eluted is indicated by a point in time when the signal of the unmodified polymer is no longer detected from the detector.