To investigate the penetration ability of near infrared diffuse light on different fruit pericarp based on chemometric methods.Pear,kiwi fruit,apple,Shatangju mandarin,fertile orange,mandarin,sweet orange,Hu You,and Shatian pomelo were analyzed and the original spectra of intact fruit,pericarp,pericarp with plastic,pericarp with metal plate were obtained.It was found that the pericarp spectra were almost the same as those of the intact fruit.The thicker the pericarp,the greater the similarity.The results showed that that the pericarp has great absorption of near infrared light.Furthermore,principal component analysis was used to cluster the four spectra. The spectral clustering results of pear,kiwi fruit and apple showed perfect differentiation,indicating that near infrared diffuse light could penetrate the pericarp of these thin-skinned fruits.According to the results of near infrared spectral clustering analysis of citrus fruits,the near infrared diffuse light could penetrate the pericarp of Shatangju mandarin,fertile orange,mandarin,sweet orange,and could not penetrate the pericarp of Hu You and Shatian pomelo.