Abstract: 4D printing is an emerging manufacturing technology, the shape, property, or functionality of the printed structure will change with time under the stimulation of external environment. Smart soft matter is widely used in 4D printing due to its large deformation, multiple excitation response mechanisms and fast response speed, especially shape memory hydrogels and shape memory polymers. At present, the control of rigidity and bending shape of soft composite is two difficult problems in the application of 4D printing, and the establishment of equivalent modulus and curvature prediction models has guiding significance for the design of mechanical properties of 4D printed composite structures. This article gave an overview of the equivalent modulus and bending curvature models of the existing 4D printed composite structures, the elastic modulus prediction models of 4D printed structures under static and dynamic conditions were introduced. Then, the application of Stoney theory, Timoshenko theory and composite material mechanics in flexural curvature modeling of soft composite was emphatically reviewed. In the end, the existing problems of the existing 4D printing soft composite mechanics prediction model and the main development direction were discussed.