Gallic acid (GAa), known as 3, 4, 5-trihydroxybenzoic acid (C7H605), usually in the form of hydrates, as an important organic raw material, is widely found in plants. Studies have shown that GAa has many effects such as anti-oxidation, anti-inflammatory, anti-tumor, anti-viral and anti-mutation. Therefore, GAa is often added to cosmetics as an antioxidant. P-Hydroxybenzoic acid (p-HA), whose molecular formula is C7H603, wherein the R group is methyl, ethyl, propyl, butyl or heptyl, respectively, referred to as ethyl p-hydroxybenzoate, Propyl p-hydroxybenzoate, butyl p-hydroxybenzoate and heptyl p-hydroxybenzoate. The p-HA ester has strong antibacterial property, low toxicity, and antibacterial action against pH, so it is often used as a preservative in cosmetics and medicines. Resorcinol (RE) is also known as 1,3 benzenediol or m-diphenol (formula C6H602). RE has a bactericidal action and can be added to cosmetics as a preservative. In this paper, three kinds of cosmetic additives such as gallic acid (GAa), p-hydroxybenzoic acid (p-HA) and resorcinol (RE) were used as target analytes, and four-dimensional fluorescence spectra were constructed by introducing a fourth dimension solvent. Three sets of experimental samples were obtained for methanol (spectral level), ethanol (spectral level), and ultrapure water, and the configuration of the three groups was the same as that of the added drug. Using the FS920 steady-state fluorescence spectrometer (spectral wavelength response range of 200~900 nm, liquid nitrogen refrigeration range of 77~320 K, excitation source power is 450 W, signal-to-noise ratio is 6 000∶1) to test the sample, and setting the excitation wavelength to 210～330 nm, a piece of data was recorded at intervals of 4 nm; the emission wavelength was 280～480 nm, and a piece of data was recorded at intervals of 2 nm. The initial emission wavelength always lagged the excitation wavelength by 10 nm, thereby eliminating the interference of the first-order Rayleigh scattering. The initial fluorescence data were then pretreated using a blank subtraction method to remove Raman scattering of the solvent. Finally, the nuclear consistent diagnosis method was used to determine the number of components of the sample to be tested to be 3, and the three-dimensional fluorescence spectrum data after pretreatment were decomposed using the alternating weighted residual constrained quadratic decomposition (AWRCQLD) algorithm. The results showed that the AWRCQLD algorithm decomposes the excitation and emission spectra of GAa, p-HA and RE almost overlapping with the target spectrum, and can achieve rapid qualitative and quantitative analysis of GAa, p-HA and RE with severe spectral overlap. Using the AWRCQLD algorithm to decompose the samples, the average recoveries of GAa, p-HA and RE were 98.3%, 98.4% and 98.1%, respectively, and the root mean square error (RMSEP) was 0.081, 0.111 and 0.001 μg·mL-1. Three-dimensional fluorescence combined with the AWRCQLD algorithm enables rapid detection of GAa, p-HA and RE in cosmetics.