Abstract: In order to improve Time of Flight Diffraction (TOFD) image quality and lateral defect resolution, a synthetic aperture focusing model for D-scan and B-scan image reconstruction was built based on fundamental principles and then some techniques contributive to image reconstruction such as matched filter, wiener filter and side lobe suppression were studied and integrated in the synthetic aperture focusing technique (SAFT). The final testing results showed that the proposed SAFT could effectively improve TOFD image quality and enhance quantitative recognition of lateral defect, thus providing an important approach of the high resolution TOFD technique.