4D printing is a kind of additive manufacturing which uses 3D printing to make the printed structure have the function of responding to external stimulus, shape changing or performance changing. The processes of 4D printing technology, such as 4D printing based on shape memory materials, 4D printing based on biomimetic composite structures and 4D printing based on field-driven smart structures, are summarized. The problems of existing 4D printing technology, such as discontinuous deformation process, difficult to prepare and difficult to realize controllable deformation, are analyzed. The 4D printing strategy for composites with continuous fibers reinforced is proposed, and the 4D printing of arbitrary deployable surface structure is realized by controlling the deformation of composites. Finally, the potential applications of 4D printing technology in aerospace, bio-medicine and soft robots are analyzed.