With consumers'increasing attention to the ingredients of skincare products and their preference for natural and additive-free products,the issue of adding preservatives to skincare products has become one of the hot topics in analytical chemistry.This article pro- poses a method based on particle swarm optimization and backpropagation neural network al- gorithm combined with surface enhanced Raman spectroscopy(SERS)to achieve quantitative prediction of preservatives such as benzyl alcohol and phenoxyethanol in skincare products for the rapid and non-destructive quantitative analysis of preservatives.We collected and an- alyzed the Raman spectra of purified preservatives such as benzyl alcohol and phenoxyethanol in skincare products and predicted their vibrational spectra using density functional theory.