In order to study the impact of operating trains on the operating performance of the bridge erecting machine in the construction of adjacent new railways, taking the newly-built Nanchang-Jingdezhen-Huangshan railway passenger dedicated project as the background, through the establishment of a numerical analysis model, the paper analyzes the lateral aerodynamic force generated during the train running near the operating line on the stress state of the whole process of bridge erecting machine in the bridge construction. The results show that the deformation state of the main beam 2 is obviously affected by the lateral aerodynamic force when the No. 1 trolley of the bridge erecting machine prepares to take the beam(Stage 1), and the maximum deformation is 4.5 mm. The stress of main beam 1 and main beam 2 are approximately symmetrically distributed in the area of 30-65 m. When the No. 1 trolley and No. 2 trolley of the bridge erecting machine are preparing to drop the beam (Stage 2), they are affected by the lifting of the concrete beam, and the lateral aerodynamic force has a certain influence on the deformation state of the two main beams of the bridge erecting machine, and the maximum difference is 2.5 mm and 3.6 mm respectively. Due to the large dead weight of the concrete beam, the lateral aerodynamic force has little effect on the main girders of the bridge erecting machine at Stage 2. However, since the maximum stress of the main girders of the bridge erecting machine is as high as 263.93 MPa, the safety factor of the structure in this state is relatively small. In order to ensure the safety during the construction process, real-time monitoring of the whole construction process of the girder is required.