As an advanced non-destructive three-dimensional (3D) imaging detection technique, X-ray Computed Tomography (CT) enables the visualization of internal structures within samples. It operates based on the interaction mechanisms between X-rays and matter, integrated with sophisticated computed tomography principles. Through detectors, it captures signals transmitted through the sample, which are subsequently processed via algorithms to reconstruct tomographic images for imaging purposes. Endowed with advantages such as high-density resolution and facile digital processing, this technology has achieved significant breakthroughs in domains including medical diagnosis and industrial inspection.  In the field of materials science, the value of X-ray CT technology is particularly pronounced: it not only facilitates in-situ 3D quantitative analysis of internal defects (e.g., pores, cracks) in structural materials but also dynamically tracks the damage evolution processes of materials under complex environments such as loading and corrosion. Via multi-scale (ranging from nanoscale to centimeter-scale) and multi-modal (including morphology, composition, and orientation) collaborative characterization, it can effectively unravel the structure-activity relationships of new energy materials, thereby providing crucial foundations for catalyst design and battery optimization.  This paper systematically synthesizes the core principles of X-ray CT technology, focuses on its frontier applications in structural materials and new energy materials, analyzes technical strengths and existing bottlenecks with specific case studies, and envisions future breakthrough pathways. These explorations not only offer directions for technological innovation to researchers but also contribute to enhancing the independent research and development capabilities of China's high-end detection equipment, holding significant strategic importance for strengthening core competitiveness.