This paper presents a calculation investigation on the Elastic-plastic incremental dy- namic response analysis of gymnasium practice hall built in Taiyuan City under the loads of EL-Centro earthquake.In this research the theory of plastic hinge is applied and the material nonlinearity is considered in the structure of the geometry nonlinear effect.The results show that: Along with the growth of the seismic wave peak acceleration,structure developed from elastic into the elastic-plastic.When it reached the limit of structure bearing capacity,the plastic development had a higher rate,much of members had reached its strength bearing capacity limit.The complete failure is due to the local instability produced by part of net rack members reversed.