Abstract: The effect of welding current, welding time and electrode force on warping deformation of lap joint during resistance spot welding were investigated by using two-dimensional digital image correlation technique. The results show that the deformation changes differently at different phases of resistance spot welding process. Under identical conditions, increasing with the of the welding current or welding time, the warping deformation induced with nugget formation increased. With the electrode force increasing while the other conditions were identical, the warping deformation induced by nugget formation reduced while that induced by electrode impact increased. The two-dimensional digital image correlation technique was used for the first time researching the resistant spot welding process and it will provide HJ1.15mmnew approach for the resistance spot welding process research and the weld quality improvement, which is of great significance for the development and improvement of the resistance spot welding process.