The Metro design quality and the construction schedule would be affected due to the lack of simple and practical software on finetuning design of the line slope of Metro works. As a result, double side control method is proposed. The determination of the double side control lines of the elevated bridges and tunnels of Metro works is systematically presented on basis of the survey data, the Metro demarcation data and the bridge data. The Metro line design software is applied in the finetuning of the line slope of Metro works, which achieves automatic and visual finetuning design of line slope of Metro works and improves the working efficiency. The method has been successfully used in the finetuning design of the slope of the airport line of Nanjing Metro. The paper can provide reference for the finetuning design of similar works in the future.