Steel reinforced concrete (SRC) structure is a kind of building structure with excellent mechanical performance, but the theory of crack width is not very clear. In recent years, the fracture energy is more and more applied to research concrete materials, which has opened up a new field for concrete materials modeling. In this paper, crack width model for SRC structure based on fracture energy concept is put forward. A uniaxial tension model is employed in the analysis for simplification. On the ground of the stress equilibrium as well as the relation among relative slip, steel strain and concrete strain, the basic equations are derived. By introducing the interfacial nonlinear bond stress versus slip constitutive relation between embedded steel and concrete, the analytical solution for distribution of slip along the interface is obtained. And based on this result, the influence of the interfacial bond-slip on tension stiffening of the steel is considered. The displacements of steel and concrete at the crack face under different load levels are computed and analyzed respectively. Finally according to the principle of work and power as well as the fracture energy concept of plain concrete, expression for fracture energy of SRC structures is obtained, and the relation of crack width and concrete fracture energy is established. The comparison shows that the fracture energy based on the model agrees with the test results well.