The process of metal corrosion is not only affected by external factors such as the environment, but also internal factors such as manufacturing techniques, alloy compositions and defects. Seeking for visualized approaches to researching the manufacturing techniques and internal corrosion conditions of metal artifacts, we used X-ray micro-CT to scan and detect a fragment of a bronze mirror and samples of archaeological and marine archaeological iron objects. Measures of XRF and XRD were also used to complement a comprehensive analysis of the component materials, manufacturing techniques and corrosion extents of metal objects. The results show that, based on micro-CT image reconstruction, the internal information of artifacts such as internal defects and corrosion extents could be measured and counted by setting different thresholds. This work provides a nondestructive research method for the study of alloy materials and manufacturing techniques as well as the corrosion assessment of metal artifacts.