The invention provides an improved digital image correlation method based on a dual-channel structural speckle cross-correlation algorithm, and belongs to the technical field of deformation measurement. The method comprises the following steps of first drawing digital images of structural speckles and random speckles according to the known dimensions of a piece under test, and making speckle templates; treating the surface of the piece under test, covering the random speckle templates on the surface of the test piece, spraying with red dye to make speckle spot patterns, covering the structuralspeckle patterns on the surface of the test piece after drying, and using blue dye to make structural speckle spots on the surface of the test piece; shooting and storing a deformed image of the testpiece, separating data of a R channel and a B channel, and respectively analyzing and optimizing the R channel and B channel to obtain more accurate image deformation data. The method realizes an improved digital image correlation method, and it is verified that the method can be applied to large deformation, rigid bodies and the like.