The present invention provides a method for relative quantitative analysis of a polymer using MALDI mass spectrometry, the method comprising the steps of: (S1) electro-spraying a solution containing a polymer sample and a matrix through a mask to prepare a plurality of polymer specimens with a thickness variation of 30% or less according to the concentration of the polymer sample; (S2) irradiating the respective plurality of polymer specimens with laser to obtain MALDI mass spectra; and (S3) creating a quantitative calibration curve from peak results of the MALDI mass spectra by using a signal of the polymer sample.