This paper describes a brief introduction to the theory and experiment concerning real-time holographic interferometry from the point of view of dynamic displacement measurements.

Dynamic fringe pattern can be observed throughout the testing by real-time holographic interferometry, while the traditional method is only suitable for static fringe pattern in phase extracting.

In the experiments of real-time holographic interferometry, some dark shadow areas appear among the interference fringes. The dark shadow areas play a very important role in the fracture process.