The project Expo Axis is one of the landmark buildings of Expo Shanghai 2010, and its structural safety depends largely on the security of the six Sun Valleys, which are the important components of the Expo Axis. The simulation of the whole process of collapse and collision of the sun valley under earthquake action is conducted in this article. In the calculation multiple nonlinear factors are taken into account, such as material nonlinearity, large displacement effect, self-contact collision among the structure members, contact collision between the structure and the ground, etc. Through analyzing the results, a reasonable assessment of the structure of Sun Valley’s performance under the supper-large earthquake is given out. This method can also offer reference to other similar large-span steel single-layer lattice structure’s performance analysis.