In the welding process, the welding parts are easy to deform by heat, which reduces installation accuracy of the components and bearing capacity of the structure. As a result, the welding partsdoes not meet the design and use requirements. So it has great significance to accurately measure thermal deformation of the welding parts in the welding process.Aimed at the problem of thermal deformation measurement of welding parts in the welding process, combined with digital image correlation method, a visual inspection method of speckle image based on timematched was proposed, by which the image acquisition quality was improved. It is verified that the accuracy of the welding deformation measurement by using this method is high through finite element simulation.The high accuracy visual inspection of welding thermal deformation of thin plate is realized by using this method