Abstract: It was comprehensively analysed the gymnasium of a college in Gansu,which was an irregular structure with multi-layer and large space.Considering the fact that its roof-spatial grid structure and lower main-body were made of two different material,it was analysed the spatial co-action principle and earthquake performance between roof-structure and its main-body,a reasonable calculating model was set up.And constructional computing program was used to calculate its anti-earthquake capability,and its calculation results were regulated manually.The design fully considered its construction measure to ensure the engineering safety.