Abstract: Based on the failure analysis of reinforced concrete and the fracture behavior of concrete as a type of quasi-brittle materials, a model of matrix crack with bridging bar is proposed in this paper. In the quasi-brittle matrix, there is a cohesive distribution force near the fictitious crack tip, and some part of the bar is separated from the matrix near the crack. According to the superposition principle and compatibility condition of deformation solid, the relationship between the stress or deformation of bar and bar's length separated from matrix under a defined far-field load is deduced by means of stress function analysis method of fracture mechanics. Numerical examples are presented and discussions are conducted for the following situations: the matrix and bar are different ideal elastic materials; a cohesive distribution force is close to crack tip; and the bar is made of elastic-plastic material.