Abstract. A method integrating terrestrial laser scanning (TLS) and finite element modelling (FEM) is proposed in this study. It aims at assessing the structural deformation of a historic brick-masonry building, the Beamless Hall at Linggu Temple in Nanjing, China. The building was composed of a series of vaults and arches, the largest among whom spans over 11m. TLS (Z+F Imager5010X) was used to collect 3D point cloud with high density. Point slices and geometric feature computation (verticality) were employed to detect geometric displacement quantitatively and intuitively. FEM-simulation was based on an ideal 3D model ignoring geometric anomalies. Results show that the Beamless Hall has inherent structural defect owing to its asymmetric layout along the transverse axis. Computing geometric feature of point cloud is fast and intuitive to detect and show geometric deviation. Inferred by FEM-simulated results and TLS-based deviation analysis, the building’s asymmetrical layout under self-weight is probably the main reason causing its structural deformation. Further developments include FEM based on as-built geometry, corrected materials parameters, and a comprehensive geometric deviation analysis.