To address the technical challenges of the synchronous close-proximity construction during the shield tunneling of Line 1 of the Dongguan Rail Transit in Guangdong Province, an analysis was conducted on the impact of the construction sequence of the shield tunnel and the intermediate ventilation shaft. A construction plan was proposed that would minimize impact and maximize economic benefits. Based on the actual site conditions, three construction plans were put forward: (1) involves constructing the ventilation shaft after the shield has passed through, (2) involves the shield passing through after the construction of the shaft's base slab is completed, (3) involves the shield passing through after the main construction of the shaft is completed. Through numerical simulation, the impact of different construction schemes on surface vertical displacement, wall-top horizontal displacement, wall-top vertical displacement, and support axial force was analyzed. From the perspective of impact and economic benefits, the optimal construction plan has been determined. Finally, the impact of the selected scheme and the reliability of numerical simulation were verified through field monitoring data. The research results indicate that the surface settlement and structural deformation are minimal after the main construction of the air shaft is completed and the shield machine passes through, although the construction period is longer. After the completion of the air shaft base slab construction, the construction period for the shield machine to pass through again and for the air shaft construction to be carried out after the shield machine passes through are similar, but the surface settlement and structural deformation are smaller after the shield machine passes through again following the completion of the air shaft base slab construction. This option also has higher economic benefits and is the preferred construction plan. The results of on-site monitoring indicate that all monitoring data are within the controlled range, the selected construction plan is safe and feasible, and the impact of construction is minimal. The measured data were in good agreement with the numerical results, validating the reliability of the theoretical conclusions. The findings provide valuable reference for similar engineering projects.