Phase unwrapping is the procedure of recovering the true phase from the modulo- 2π phase. It is needed for many applications such as Interferometric synthetic aperture radar, MRI and X-ray phase imaging etc. Many phase unwrapping methods have been proposed for two dimensional phase image. Nevertheless, unlike the conventional phase image, differential image are directly measured by many X-ray phase imaging such as Talbot interferometer. And these are also wrapped image. Compare with phase image, we need an additional integral operation after the unwrapping. It is not obvious whether we can get correct results using existing unwrapping methods directly. For example, integration may result errors propagation along the whole path. In this paper, we analyze various existing unwrapping methods with differential image. We also analyze integration methods how to affect the final result. And then propose our technique to get better results, which is the first attempt for unwrapping with differential image. Several experimental results demonstrate that proposed technique is effective.