Abstract: The shear lag effect, the shear deformation and the self-equilibrium condition for the T-beam with two-ribbed slabs are considered in the present study. Two generalized displacement functions are employed to analyze the mechanical characteristics, and the corresponding four ordinary differential equations with natural boundary conditions are derived. Then, the closed-form solutions for the generalized displacements are obtained. Furthermore, the contributions of the self-equilibrium condition, the shear lag effect to the stress and the deflection of the T-beam with two-ribbed slabs are analyzed in detail. It is concluded that the mechanical analysis of the T-beam with two-ribbed slabs is more accurate. The numerical simulation using the finite element algorithm by the ANSYS validates the proposed approach. Thus, our theoretical analysis provides more insights than the share lag theory of the T-beam with multi-ribbed slabs.