Abstract: In order to study the seismic performance of a S-shaped irregular elevated curve bridge under earthquake，a Sshaped curve bridge model with the similar ratio being 1/20 was designed and produced，to analyze the experimental phenomena，the dynamic characteristics，acceleration and displacement test data of the model bridge in the processes of tests． The results showed that the S-shaped curve bridge during the whole test process，the self vibration frequency of the structure decreased significantly and the damping ratio increased significantly． The peak acceleration on the bottom of the pier was less than that on the top of the pier under frequent earthquakes; the peak acceleration on the bottom of the pier was larger than that on the top of the pier due to very serious torsion of pier beam under rare earthquakes． Pier beam radial relative displacement was larger than the relative tangential displacement in frequent earthquakes; pier beam radial relative displacement was less than the relative tangential displacement in rare earthquakes．