Abstract: By participating in the international capability verification activity of"Determination of Preservatives in Cosmetics",the technical level of cosmetics testing was improved.According to the high performance liquid chromatography in the Cosmetic Safety Technical Specifications(2015 edition)and the capability validation work instructions provided by the Netherlands Institute for Interlaboratory Studies Spijkenisse(IIS),the contents of methyl chloroisothiazolinone,phenoxyethanol and propyl 4-hydroxybenzoate in cosmetic samples were determined.The three preservatives showed a good linear relationship with the peak area in the corresponding concentration range,the correlation coefficient(R2)was above 0.999,and the recovery rate was between 93.82%and 101.86%.By means of spiked recovery,reference material verification and personnel comparison,the accuracy of the results was well controlled.The Z values of the capability verification results were:methyl chloroisothiazolinone 1.72;Phenoxyethanol 0.72;Propyl 4-hydroxybenzoate 0.52.The Z values are all less than 2.In the end,the laboratory achieved satisfactory results in the IIS capability verification.The results showed that the quantitative determination ability of three preservatives(methyl chloroisothiazolinone,phenoxyethanol and propyl 4-hydroxybenzoate)in cosmetics was good.