Abstract: A new hybrid structure arranging a double-layer shell between truss strings was proposed in the project-roof design of the Exhibition Center in Erdos Dong-sheng Sports Center.The new structure system not only meets the demand of adapting to an irregular large-span roof,but also increases the structural stiffness and stability.Model examples close to the actual project was designed.The effects of sag-to-span ratio,initial prestresses and the numbers of struts on the static and dynamic behaviors and the steel consumption of the integral structure were fully analyzed by concerning the integrate model.Based on the research result of model examples,the irregular roof of Erdos Dong-sheng Exhibition Center was designed.Besides,the design of the pre-stressed cable is difficult and critical,and a detailed method and the corresponding reference to adjust the pre-stressed cable were provided.