A method for relative quantitative analysis of a polymer using MALDI mass spectrometry, the method comprising the steps of preparing a plurality of polymer specimens having a thickness variation of 30% or less by electrospraying a solution including a polymer sample, a monomeric internal standard material, and a matrix through a mask for each different concentration of the polymer sample; obtaining MALDI mass spectra by irradiating laser beams to each of the plurality of polymer specimens, and calculating a signal intensity ratio of the polymer sample to the small molecule internal standard from peak results of the spectra; and depicting the calculated signal intensity ratio according to the concentration of the polymer sample to prepare a quantitative calibration curve, and the method capable of providing MALDI mass spectra with reduced overlapping peaks and thereby providing the relative quantitative analysis of a polymer with improved accuracy.