A kind of light-duty automation system is presented for the automation of detecting and grading eggs, namely system of intelligent robot detecting and grading eggs(SIRDGE). This system enables crack detection, inner quality detection and eggs conveying to be combined. All these tasks are done by a joints robot and the whole process of detecting and grading is automatic. The frameworks and work course of the system are presented. Necessary explanation of the main hardware and the software is made, which includes how to capture image by scene video camera and the camera calibration, algorithm for processing images and distilling eigenvalue from them, motion controlling and trajectory planning of the robot when detecting and grading eggs, single chip micyoco program for controlling the suction cup, processing the sounds by tapping egg shell and the crack egg detection, color image processing and inner quality of eggs detection, etc. Some tests are done and the test parameters are given.