Based on simplified stress-strain relationship of fiber reinforced concrete and the plane section assumption and equilibrium equation, the curvature of reinforced concrete columns with fiber reinforced concrete in plastic hinge region under different ultimate state was derived. Then, the distribution force in the cross section was obtained by calculating the curvature under different ultimate states. By taking the distance of the cross section centroid axis, the moment expressions of reinforced concrete columns with fiber reinforced concrete in plastic hinge region at crack load point, yield load point, peak load point and ultimate load point were attained. The calculated values agree well with the experimental results.