Abstract:At present， the requirement of food industry for its product packaging was higher and higher in Chi－ na. The printing was a key factor in the product packaging process for attracting customer. Printing had caught the attention of many enterprises and researchers. Food packaging and printing defect detection system intro－ duced in this paper， mainly including image preprocessing part. In this paper， traditional wavelet transform al－ gorithm model and a modified wavelet transform algorithm model were established. Simulation experiments on the accuracy of both methods were analyzed. Results showed that the modified image wavelet transform algo－ rithm could improve food packaging printing defect detection accuracy， and realize the nondestructive detection.