The seismic safety evaluation of existing urban buildings （groups） is faced with multiple technical development of effi‐ cient analysis， rapid evaluation and quantitative determination. Considering the evolution of structural performance during the longterm service life， the safety evaluation of in-service buildings requires design and measurement information on the structures as well as regional ground motions to calibrate the real conditions of the structures， which can ensure the accuracy of the performance eval‐ uation results within an acceptable timeliness. Based on the equivalent nonlinear single-degree-of-freedom model and the authors’ recent research on data-driven performance assessment index， this study proposes a method to map the global conditions of the structure with the measurement modal information and assess the seismic safety of the target building using the regional dataset of measured ground motion further. Based on the field testing and the HAZUS technical manual， the procedure of establishing the equivalent nonlinear single-degree-of-freedom representing the existing building is described. Two structural condition evaluation in‐ dicators are proposed， combined with multivariate engineering performance parameters， and the relationship between the deforma‐ tion of an equivalent model and different seismic performance levels is further established. A high-rise regular RC frame structure lo‐ cated in Gongxian， Sichuan Province is considered as an example， the seismic safety of this building subjected to 10 local earth‐ quakes measured from 2019 to 2022 is evaluated.