A long-span elliptic paraboloid suspended dome structure,in which the clear span between supports is 110m ×80m and the rise of the upper single-layer reticulated shell is 9. 4m,is employed in the steel roof of Houjie Gymnasium.The imperfection sensitive regions of the structure and the corresponding single-layer reticulated shell are comparatively investigated by means of the advanced random imperfection mode method.On this basis,the in- fluences of the local topological form change and the half-span distribution of the live loads on the imperfection sen- sitive region of the suspended dome are further discussed.The results show that (1) the imperfection sensitive re- gion of the suspended dome is located in the upper single-layer reticulated shell; (2) the imperfection sensitive re- gion of the suspended dome is significantly different from that of the corresponding single-layer reticulated shell,and owing to the introduction of the lower cable-strut system,the imperfection sensitivity of the upper single-layer reticulated shell is remarkably improved; (3) by changing the local topological form,the imperfection sensitivity of the structure can be effectively reduced; and (4) the half-span distribution of the live loads has little influence on the imperfection sensitive region of the suspended dome with a traditional topological form,but has a significant in- fluence on the central region of the upper single-layer reticulated shell of this kind of suspended dome.