Abstract: In order to examine the deformation during metro tunnel construction and operation, the terrestrial laser scanning technique (TLS) was used for rapid collection of point cloud data. After such processing as denoising and rectification of the collected scattered point cloud data, sections were obtained by applying the slicing technique. Based on this, the center coordinate and radius of one circle was calculated by the least square method and the convergence conditions were determined by comparing the calculated values with the design values. In order to monitor the deformation of the same segment over different periods, two groups of data were collected to establish the variation curve to analyze the deformation changes. The test results show that, compared with the traditional method for convergence monitoring, this method is feasible and accurate since it greatly improves the working efficiency, reduces the working intensities and shortens the monitoring cycle.