A class of FeCo/epoxy magnetostrictive composites is prepared in this study to explore the effect of the structural design of composites on the magnetostrictive properties. The experiments are divided into two groups according to the shape of the FeCo wires: to fabricate the FeCo/epoxy magnetostrictive composite, one experimental group uses twisted FeCo wires while the other uses straight FeCo wires. An experiment on harvesting bending-energy is conducted for these two groups to analyze the effect of the residual stress stemming from the twisted structure on domain rotation or wall movement. By considering the magnetization and magnetostrictive curves, this work provides insights into the mechanism responsible for the improvement in magnetostriction of the magnetostrictive composite due to the effect of structural design. This study offers another concept of structural design differing from modification of the composition to improve the magnetostriction of the magnetostrictive composite. Meanwhile, this work also avoids reduction of the magnetostriction due to the discontinuous magnetostrictive powder and fiber that occurs in certain traditional magnetostrictive composites.