The invention discloses a real-time detection method of a digital image correlation method based on SIFT improvement, and relates to a deformation detection method. The method comprises the following steps: 1, obtaining gray level images before and after deformation; 2, calculating sub-pixel curved surface fitting; 3, calculating a sub-pixel interpolation; 4, establishing different Gaussian scale spaces to construct a continuous scale image pyramid; 5, searching and screening feature points from the continuous scale space; 6, constructing analysis sub-regions in combination with the selected feature points; 7, calculating the displacement of the deformation sub-region; and 8, using a displacement feature vector to represent deformation. According to the method, the continuity of the displacement field is ensured, the adjustment of the calculation speed and precision is more concise and convenient, the two parameters are balanced, the improved algorithm does not increase the calculation complexity, the pretreatment time is saved, the method has better adaptability to complex boundaries, and higher calculation precision can be achieved under the condition of the same calculation speed.