Aiming at the problem that digital holography technology measures three-dimensional micro-deformation on the surface of an object, which requires vector information in three different directions, and usually the detection optical path is relatively complicated, a three-dimensional deformation detection method based on multi-camera digital holography is proposed. First, a method is established to accurately reconstruct the phase difference distribution before and after the object. According to the three phase differences that are not coplanar and contain three-dimensional deformation information, the detection of the three-dimensional deformation field on the surface of the object is realized. Then, numerical simulation and experimental verification of the proposed method are carried out, which proves the feasibility and practicability of the method.