Dynamic strain monitoring of rotating blisk is critical for its operational reliability. Traditional vibration monitoring systems for rotating blisk are often limited to solving the dynamic strain at a few localized points, and it is difficult to obtain the dynamic strain of the panoramic view of the blisk. In addition, when considering the multimodal vibration situation, strain and stress distributions in blades differ from unimodal vibration. Under these circumstances, the traditional strain gauge method cannot accurately obtain the strain distribution, and the inversion is more complicated because the vibration situation of the blisk needs to be decoupled firstly in the calculation process. To address these challenges, this paper proposes a dynamic strain rapid inversion method. This method directly computes dynamic strain at any blade point based on tip vibration displacements measured via blade tip timing, provided that vibrations conform to a single-mode family. Through theoretical analyses and experimental validation, using the dynamic strain rapid inversion method, the method employed in this paper can predict the dynamic strain at any point on the blade under resonant conditions. In the experimental process of the first mode, family inversion error is maximum 15.9%. The speed of dynamic strain inversion can be improved by using the method in this paper.