Carbon-fiber-reinforced polymer (CFRP) composites are widely applied in various important structural components. One of the critical issues in the successful application of CFRPs is the assessment of damage state in a particular structural component. This work describes open electrical impedance tomography (OEIT) as a novel method for damage detection in unidirectional CFRP panels. Different levels of damages such as impact damage, delamination, fiber break, and transverse crack are simulated for verification. Direct differential imaging based on OEIT is proposed for damage recognition and as well as relative voltage change curves. The results indicate the ability of OEIT for not only damage detection, but active structural monitoring as well.