Abstract: For high-speed, high-resolution images of steel strip surface online inspection, a machine vision system based on TDI (Time Delayed Integration) imaging technology was researched and developed. TDI CCD sensor was used and cooperated with adaptive illumination LED light in this system. The acquired images of steel strip were sent to the image splitter through the fiber and then real-time processed by the Image Processing Units (IPU). Surface defects on tin strip were detected in this system. Application and results show effectiveness for tin strip surface defect inspection of the system (SIS) based on TDI(Time Delayed Integration) imaging technology.