Abstract: Carbon fiber reinforced composites (CFRCs) are extensively employed in engineering applications owing to their outstanding mechanical properties. Nevertheless, the transverse tensile mechanical behavior and failure mechanisms at the fiber-matrix interface remain inadequately explored. In this study, CFRC specimens were fabricated and subjected to in situ computed tomography (CT) scanning at incremental load stages during transverse tensile testing. Post-loading CT datasets were processed to reconstruct three-dimensional (3D) models of the specimens, quantify internal pore distribution, analyze porosity evolution, and characterize crack initiation and fracture morphology. Additionally, digital volume correlation (DVC) was implemented to investigate the three-dimensional strain field within the loaded specimens. The results demonstrated that CFRCs exhibit a high initial porosity of 1.4%, with porosity increasing by 3.69 times (reaching 5.16%) from initial loading to fracture onset, indicative of rapid damage accumulation. DVC-based strain field analysis successfully identified localized strain concentrations, enabling precise prediction of ultimate fracture locations.