In order to study whether the standing seam roof system installed on a flexible roof structure has the ability to adapt to the large deformation of the flexible roof structure and whether panel details of the roofing system can ensure the water tightness under large deformation, taking the roof structure of the swimming stadium in Suzhou Industrial Park Sports Center as an example, a 6.6m×6.6m test unit was used to design the full-scale water tightness test of the metal roofing system under large deformation. Through numerical analysis, stress and deformation distribution of the roofing system was explored under large deformations in the flexible roof structure. A refined finite element model was also established to evaluate the water tightness of key details in the standing seam roof panels. The test and analysis verified that the standing seam roof system had the ability to adapt to the large deformation of the flexible roof structure, the calculated angle between standing seams was only 2.18°，and water tightness can be ensured at the same time.