Abstract: Vision is playing an important part in robot system.It can not be lacked for second generation robotsand intelligent robots.When the working environment is changed,the robot can adapt the environment toit.A flexible assembly automation is a typical with vision sensor.This paper discussed an experimental system and some fundamentals of visual control including robotcontrol,image acquirement,2-D feature extraction,system calibration and the system structure,as well asrecognition,location and orientation of parts.Finally,assembly was realized.