This paper introduces the structural characteristics and configuration of the butterfly valve of the big bore in the 2.4 m transonic wind tunnel, analyzes the reasons for the fracture of the valve stem of the butterfly valve, obtains the main factors for the fracture of the valve stem, and formulates the corresponding maintenance plan and the methods for use, maintenance and maintenance in the future. The results show that the analysis can provide a reference for improving the service life of the valve and reducing the risk of the equipment.