In this study, a system for measuring thermal strain in micro region of electronic packages using the digital image correlation was developed, and applied for measuring the distribution of strain in a cross-section of a print circuit board (PCB) during thermal cycle test. The warpage of the PCB expected from the measured strain accurately corresponded with the macroscopic warpage measured using a laser displacement meter. The accuracy of measured displacements was affected by image distortion caused by an optical system. An error correction method using a piezo stage was proposed to improve the accuracy of the system.