88.57%。 The hyperspectral imaging technology was proposed to detect the subtle bruises on fruits. Apples were adopted as the experimental object. The apples’ hyperspectral images between 500 nm and 900 nm wavelength were analyzed via the principal components analysis, and the feature images under 547nm wavelength were selected to detect the bruises on apples. The asymmetric brightness of the images was eliminated with asymmetric second difference subsequently. Finally, the feature of bruise was extracted through appropriate image processing. The experimental results show that detecting subtle bruises on fruits on-line with hyperspectral imaging technology is realized and the accuracy is 88.57%.