Abstract: The internal force distribution of cable-membrane structures is related to the spatial configuration. The actual configuration of a cable-membrane structure in service is different from that in design state due to the geometric shape finding during the construction phase, the structural damage and the performance degradation during service phase. Since the service behavior is unknown, the engineering safety assessment is difficult to operate and there is no reliable method for reference. A finite element model updating method was proposed for in-service cable-membrane structures based on spatial configuration indicators. The initial prestress of the cables in the model is used as the optimization parameter, and the coordinate of the key nodes of the structure is used as the model updating objective function. The objective function based on the spatial location information of the feature points is constructed to reflect the coincidence degree between the finite element model and the actual structure. The ABAQUS and MATLAB co-simulation optimization program is designed, and the model is updated by global search and local optimization. In the field test, 3D laser scanning was used to obtain the spatial configuration information of the in-service cable-membrane structure, and the finite element model was updated based on the measured data. The force of the updated model is closer to the actual structure. The comparison with the actual measurement results of the cable force shows that the cable force of the finite element model is reduced from the maximum deviation of 10%~30% before the correction to within ±10%, which verifies the effectiveness and accuracy of the method. The updated finite element model is used to perform the safety assessment of the in-service cable-membrane structure.