Abstract:The development of electronic devices towards integration，thinness and miniaturization requires copper slabs and strips not only to have good performance，but also to meet high precision and high surface quality. The surface defects of copper slabs produced by horizontal continuous casting after cold rollingin a certain enterprise were studied，the macroscopic morphology of various defects is observed，the mechanism of formation is studied by means of optical microscopy，scanning electron microscopy，energy spectrum analysis and industrial CT，and the causes of surface defects and improvement measures are discussed，which provides reference for production practice.