Abstract: As a new type of composite building material, steel fiber reinforced concrete can make up for the short? comings of ordinary concrete such as low tensile strength and poor toughness, and thus has good engineering mechanical properties, but its application lacks clear theoretical support. This paper studies the post-cracking plastic behaviors of steel fiber reinforced concrete through the three-point bending test of a notched beam. By adopting the post-cracking linear softening model as the material model of the shield tunnel segment, and based on the principle of internal force equivalence, the residual plastic axial tensile strength under the post-cracking linear softening model is obtained, which is expressed by the residual elastic flexural and tensile strength. Through the sectional static equilibrium equation and the introduction of residual plastic axial tensile strength, the formula for calculating the normal section bearing capacity of steel fiber reinforced concrete structure is obtained, which is applicable to large and small eccentric compression conditions, improving the calculation system of the normal section bearing capacity of steel fiber reinforced concrete segments. Through the full-scale segment test, the rationality of the material model and the normal section calculation method is verified.