In order to quantitatively characterize the degree of deformation mismatch of adjacent layers of composite flexible electronics, an experimental system based on digital image correlation (DIC) and a method of evaluating deformation mismatch are designed. First, a composite flexible electronic sample was prepared, and the experimental system was verified through translation experiments. Second, the sample was uniaxially stretched at different temperatures and the Von Mises strain was calculated. Finally, the degree of deformation mismatch was Characterized by defining the patterned strain fluctuation index P. The experimental results showed that the translation error of the experimental system was within 1%, which meets the requirements of deformation measurement. The sample was stretched by 2 mm at 50 ℃ , and the maximum and minimum strains of Von Mises differed by about 65%. The sample showed deformation mismatch with uneven strain value but uniform strain distribution. Under the same tensile conditions, the degree of deformation mismatch changed little from 25 ℃ to 75 ℃ , and it changed significantly at 100℃ , the increment was about 60%. This method effectively characterizes the degree of flexible electronic deformation mismatch.