In order to study the flexural performance of pre-fabricated integrated floor truss beams under eccentric loads so as to improve the beam design for its application in actual projects. This paper proposes a new type of fabricating truss girder connected by high-strength bolts. And taking Yuyan Tower as an example, this paper conducted an elastic loading test for code compliance verification and a destructive test of ultimate bearing capacity for the pre-fabricated truss beams, with a focus on the mechanical performance of the truss beams, joint interface shear resistance, destructive mechanism, and deformation law of the truss beams. The results showed that under eccentric loads, buckling failure occurred at the diagonal webs and end vertical webs of the truss beams under compression, and no sliding and friction energy dissipation occurred at the connection joints, which was in accordance with the design principle of “strong joints and weak members” as stipulated in the design code. Compared with the designed load, the ultimate bearing capacity of the truss beams was increased by 80.5%, inhibiting sufficient safety reserve. Also, the truss beams showed good overall stability and safety. After the truss beams were unloaded, the tension displacement and vertical displacement from the middle part to the lower part of the span could recover up to 78% and 83% of the maximum displacement respectively, indicating that the truss beams had strong deformation resistance. Through theoretical derivation, the theoretical value of shear resistance at the splice joints was found to be higher than the experimental value, which implied that the performance of the shear bolts at the joints was not fully developed and the structure design was relatively safe. The results of the study can provide important experimental data and theoretical basis for the actual projects, which can offer scientific guidance on project design and construction and is of great significance to the sound development of pre-fabricated buildings.