The corrosion process of copper in thermal flow system was investigated through the experimental bench. According to surface variation of samples during corrosion process, the surface model of specimen was build up based on Gaussian filter. The results show that the corrosion characterization of copper in thermal flow system is pitting corrosion. The morphology characterizations of metal corrosion process can be described using the proposed surface model. The generation and development of copper pitting process can be observed clearly.