<p>The modal analysis of the label-free visual analysis structure proposed in this paper is a new measurement method that slices the continuous high-speed camera sampling video, and compares the pixels of the region of interest one by one with the digital image correlation algorithm to obtain the vibration response information of the measurement points. While ensuring the accuracy and robustness of the measurement and analysis results, the label-free measurement improves the data processing efficiency. Secondly, the digital image correlation algorithm combined with the inverse Gaussian-Newton method was used to obtain the full-field dynamic displacement. Finally, the random subspace method based on covariance is used to identify the modal frequency of the structure. To verify the effectiveness of the proposed method, the vibration response of the Charpy structure is measured by using a high-speed camera and an accelerometer sensor, and the results show that the relative error between the proposed visual measurement method and the eddy current sensor for the first six modal frequencies of the Charpy structure is not more than 1.17 %. The experimental data have good consistency, which can be widely used in the structure’s vibration displacement measurement and modal frequency recognition.</p>