3 600枚/h。A testing and grading device of the cracked egg based on DSP was presented. The device consists of front end circuits and trailing end circuit. The front end circuits include detecting and modulating signal circuit, a circuit of threshold trigger and A/D conversion and the interface with digital signal processor (DSP). The trailing end circuit is a driving circuit for the grading machine. When the system worked steadily, it could detect 3 600 eggs per hour. The detecting accuracy of the system is 93.22% for intact eggs and 85.61% for the cracked eggs. And the total detecting accuracy is 89.2%. 