The invention relates to a method for approaching a high boiling-point polyol purity true value through correction. The method comprises the following steps: performing complete esterification on a high boiling-point polyol sample by using excessive acetic anhydride, measuring a chromatographic response mass correction factor of peracetic esterification of known impurity in the high boiling-pointsample by using an addition weighing method, separating the product after esterified organic components in the sample by using a temperature-resistant chromatographic column, and measuring the mass fraction of the peracetic esterification of the main component of the high boiling-point polyol by using a correction area normalization method, and representing the mass fraction of the main componentof the high boiling-point polyol in the sample before esterification by using the mass fraction of the peracetic esterification of the main component of the high boiling-point polyol when the mass fraction of the peracetic esterification of the main component of the high boiling-point polyol is not less than 95%; and correcting the moisture in the sample so as to compute the purity of the high boiling-point polyol. The method disclosed by the invention has the advantages of realizing convenient separation, and accurate measurement of the purity of the high boiling-point polyol.