With the increasing demand for industrial product quality and safety verification, conventional nondestructive testing (NDT) technology is hardly able to fulfil the specialized requirements such as real-time monitoring, on-line inspection and rapid detection, which brings the emergence of visualized NDT. It is clearer, more intuitive and accurate to apply visualized technology to the detecting and estimating of product quality, which is much significant for higher detecting efficiency and accuracy, as well as for large-scale industrialization, informationization and intelligentization. This paper summarizes the research progress on visualization technology applied in NDT. First, the following aspects: ultrasonic testing, infrared thermal wave testing, electronic and magnetic testing, computerized tomography and some automated NDT techniques as well as their visualization methods are introduced. Then, the range of application, merits and demerits of each technology are analyzed. At the end, the improvement and development prospect of visualization technology used in NDT is forecasted.