Thermal protection tile composites are widely used in the aerospace field due to their excellent high-temperature resistance. However, internal defects are prone to occur during service, posing potential threats to aircraft safety. Therefore, conducting nondestructive testing research on thermal protection tile composites holds significant engineering importance.This study systematically investigates the nondestructive testing of thermal protection tile materials with prefabricated hole defects based on a THz-TDS system. A reflective terahertz scanning system was used to acquire time-domain signals from the samples, and the Savitzky-Golay filtering algorithm was introduced to optimize signal denoising. Key feature parameters were then extracted to construct imaging. To address the limitations of single-parameter imaging in defect detection accuracy, an innovative detection method combining wavelet image fusion and the Canny edge detection algorithm was proposed.Experimental results demonstrate that this method not only achieves a 100% recognition rate for all prefabricated hole defects but also controls the detection error within 0.5 mm for hole defects with diameters of 10 mm and 5 mm, with a relative error not exceeding 6%. This high-precision detection method provides technical support and methodological reference for the intelligent development of defect detection in thermal protection tile composites.