Abstract: The traditional strengthening technology of building connecting corridor is easy to be affected by the tensile control force of concrete, resulting in the phenomenon that the stress and displacement of steel pipe are quite different from the actual data, which leads to the unsatisfactory reinforcement effect and seriously affects the construction quality and construction safety. In view of this, a new construction analysis and research of external prestressed reinforcement engineering of building connecting corridor was proposed. Taking the steel structure project of Sichuan Guantang Architectural Engineering Design Co., Ltd. as the research object, the reinforcement construction scheme of GL6, GL3 and GL4a in connecting corridor (一) and connecting corridor (二) was designed according to the structural reinforcement design drawings. After the completion of lifting and unloading, the external prestressed tension construction of the secondary beam of the corresponding team was carried out. The tensile length value, section area, bending radius and relative upward displacement value of the prestressed tendons were calculated by local cutting, so as to determine the reasonable tensile tension and prestress. The contact analysis of the steering block with external prestress was carried out by finite element ANSYS, and the finite element combination model of the steering gear was constructed. The vertical and transverse components of the external prestress bundle were applied. The external prestressed reinforcement engineering of the building corridor was divided into three construction parts:steel structure reinforcement, steel beam cutting reinforcement and bull leg reinforcement. Firstly, the pressure sensor was added to the unloading support point of the corridor, and synchronous grading counterjacking was used to support the steel plate, and the internal force generated by the prestress was used to offset the local force. The counterjacking force was controlled according to the synchronous value of the pressure sensor, to strengthen the steel structure. Plasma cutting machine was used to cut the steel beam and Q345B steel plate was used as the new flange. The new flange and the original structure need to be fully welded to ensure the construction quality of welding. The remaining section of the steel beam after cutting was reinforced by spot welding with the discontinuous weld of 20-30 mm, so as to complete the cutting and strengthening of the steel beam. According to the steps of material approach acceptance- processing of steel plate material number-drilling and anchoring of steel bars-gouging of the surface of the original reinforced beam-cleaning of the surface of the beam-installation of the processed steel leg-gluing of steel plate and the original leg-maintenance-acceptance, the reinforcement construction of the leg part was completed with planting reinforcement materials. In order to verify the reliability setting experiment studied in this paper, two working conditions, normal loading and ultimate loading, were designed, and the deformation state of the corridor was monitored during the reinforcement process. It can be seen from the experimental results that, using the external prestressed reinforcement engineering scheme of the building connecting corridor proposed in this paper, there was a maximum error of 0. 5 MPa between the stress analysis results and the actual stress analysis results in the X direction, and a maximum error of 2. 0 mm between the displacement analysis results and the actual displacement analysis results. The experimental results showed that there was a small difference between the studied method and the actual data. It could design effective reinforcement construction scheme on the basis of analyzing external prestress and tension, and provide technical support for stable construction of building corridor.