The electromagnetic effects caused by the parallel proximity or crossing of UHVDC transmission lines and oil and gas pipelines were analyzed using the business software. Electromagnetic calculations were conducted for a ± 800 kV UHVDC transmission line located in a specific area, with emphasis on its impact on adjacent metallic pipelines. Simulations were carried out under three operating conditions of the DC transmission line: normal operation, short-circuit fault, and lightning strikes affecting the transmission towers. The induced interference voltage and coating voltage on adjacent pipelines were evaluated. The electromagnetic impact of the ±800 kV UHVDC transmission line on nearby metallic pipelines was quantitatively assessed by comparing the simulation results with relevant standard limits. The results showed that under all three conditions—normal operation, fault, and lightning—the electromagnetic effects were found to be within the specified safety limits. The findings of this study are of practical significance for ensuring the safe operation of UHVDC transmission lines and oil and gas pipelines within shared corridors. Moreover, useful references are provided for the design of related engineering solutions.