Abstract: Aiming at the problems of undetected tinny defect of  1.0 mm and near surface dead zone, a scattering-based ultrasonic testing method of vertical launch ultrasonic and backscattering was proposed in the paper, which analyzed the characteristics of sound distribution and illustrated testing principle. Through the artificial defect testing, the feature of tested signal, sensibility and image are recognized. The reliability of scattering wave sound field distribution is tested by finite element analysis. The experimental results show that ultrasonic scattering test can identify the near surface defect and tinny defect that can not be distinguished by conventional ultrasonic test, and the near surface defect with buried depth 1.0mm and  0.4 mm can be effectively detected.