Abstract: The key points of automatic real-time monitoring of the structural deformation are introduced when the subway Line 1 is traversed by the extension section of the subway Line 2 in Shenzhen. The automatic monitoring system is improved according to the structural characteristics of the shield tunnel, and the structural deformation rules are analyzed. After all the traversing of the left and right tunnels of subway Line 2, the accumulated settlement is -13.8 mm, which is below the critical value. The settlement process is divided into three stages. For the second stage with the largest settlement, a logarithmic function y=-4.096ln(x)-2.7194 is employed, and the fitting results are satisfactory. The main reasons of the structural deformation induced by the shield method are discussed. It may provide reference and monitoring experience for similar projects in the future.