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. Based on the characteristics of real-time holographic interferometry fringe pattern and Hilbert transform, the method of phase extracting with Hilbert transform is presented for real-time holographic interferometry fringe pattern. High-Pass filter method is used to reduce the influence of the bias intensity, and the fringe pattern phase change has been obtained in the experiment of aluminum deformation. The experiment results show that the Hilbert transform method can be applied to dynamic fringe pattern in phase extraction and extract the phase difference between any two moments at any point in the field of real-time holographic interferometry. Moreover, the automatic measurement results are consistent with man-made results.