Abstract: The precast utility tunnel is assembled in the middle of the sidewalls and connected by prestressing tendons, and its connection joints can both rotate relatively and transfer bending moment with semi-rigid characteristics. The beam-line model plots the moment–rotation straight line of the semi-rigid beam (demand line) and the moment–rotation curve of the joint (performance line) together, and the joint rotational stiffness can be determined through the intersection of the two. Using the experimentally validated Abaqus finite element model, a finite element analysis of the bending performance of the joint with the splice interface stress and sidewall thickness as the main parameters was carried out. Based on the results of the finite element analysis, a beam-line model is proposed for the structural design of precast utility tunnel connected by prestressing tendons.