Auricle defects are important and common occurrences in forensic medicine. The accurate measurement and assessment of auricle defects is key to identifying and evaluating injury, and the currently available methods are known to be labor intensive and inaccurate. In this paper, we introduce an identification and documentation of auricle defects solution, which consists of an optical three-dimensional (3D) method and an effective algorithm to calculate the maximum projection area and identify auricle defects. In this study, three separate examiners measured 40 auricles of 20 adults using 3D optical measurement and two other commonly used methods to investigate the validity and representative reliability of 3D optical measurement for auricle defect identification. Based on the statistical analysis, the 3D measurement method is valid and showed a better reliability than the reference methods. We also present a representative auricle defect identification case using the proposed 3D optical measurement method. The study concludes that the optical 3D measurement method is a reliable and effective tool for auricle defect identification.