Abstract: The entire bearing capacity and the synergistic deformation of the initial support of tunnel are significantly impacted by the bond-slip behavior between I-shaped steel and shotcrete. The push-out tests of natural bonding and welded studs were conducted to observe the failure characteristics of the specimens and obtain the bond-slip curve. On this basis, the specimen’s bond-slip behavior was analyzed, and the bond-slip constitutive models of natural bond and welded stud specimens were established. The calculation formula of eigenvalues was proposed. The test results exhibit that the failure mode of the natural bonding specimen is longitudinal splitting failure, the welding stud specimen falls in tensile failure, and the tensile cracks occur along the transverse direction of the stud. The specimen’s load-crack width curve is consistent with the average bond strength-slip curve, divided into four stages, i.e., no slip stage, inclined upward stage, downward curve stage and residual horizontal stage. Adding stud connectors to steel webs can improve the characteristic bond strength of steel shotcrete. The fitting between the test curve and the constitutive model curve is high, indicating that the constitutive model proposed in this paper has high accuracy. The research results provide theoretical support for the research on failure characteristics and the design of tunnel I-shaped steel and shotcrete support structure.