An on-line system based on acoustic resonance was developed for eggshell crack detection. The system employed digital signal processing (DSP) as core processor to collect and analyze the response signal of shell eggs. The effects of excitation point, speed of the conveying system, impact intensity and egg mass on the frequencies response signals were investigated. Based on previous experiments, differences between the signals of intact eggs and cracked eggs were analyzed. Five excited resonance frequency characteristics expressing the differences between intact and cracked eggs were explored as input vectors. A simple and robust calibration model was built to discriminate intact and cracked eggs, while meeting speed requirement of on-line measurement. The identification rates for intact and cracked eggs were 100% and 96.1% respectively. It is concluded that the system has significant potential in the on-line detection of cracked eggs. (C) 2012 Elsevier Ltd. All rights reserved.